Attachment 167185 Details for Bug 207342 – The updated faq file

The updated faq file

book.xml (text/xml), 262.05 KB, created by danthemangorman on 2016-02-19 17:52:49 UTC

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Created: 2016-02-19 17:52:49 UTC

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><?xml version="1.0" encoding="iso-8859-1"?>
><!DOCTYPE book PUBLIC "-//FreeBSD//DTD DocBook XML V5.0-Based Extension//EN"
>	"http://www.FreeBSD.org/XML/share/xml/freebsd50.dtd" [
><!ENTITY bibliography SYSTEM "../../../share/xml/bibliography.xml">
><!ENTITY rel.numbranch "3">  
><!ENTITY rel.head "<emphasis xmlns='http://docbook.org/ns/docbook'>11-CURRENT</emphasis>">
><!ENTITY rel.head.relx "11.<replaceable xmlns='http://docbook.org/ns/docbook'>X</replaceable>">
><!ENTITY rel.head.releng "<symbol xmlns='http://docbook.org/ns/docbook'>head/</symbol>">
><!ENTITY rel.relx "10.<replaceable xmlns='http://docbook.org/ns/docbook'>X</replaceable>">
><!ENTITY rel.stable "<emphasis xmlns='http://docbook.org/ns/docbook'>10-STABLE</emphasis>">
><!ENTITY rel.releng "<symbol xmlns='http://docbook.org/ns/docbook'>stable/10/</symbol>">
><!ENTITY rel.relengdate "January 2014">
><!ENTITY rel2.relx "9.<replaceable xmlns='http://docbook.org/ns/docbook'>X</replaceable>">
><!ENTITY rel2.stable "<emphasis xmlns='http://docbook.org/ns/docbook'>9-STABLE</emphasis>">
><!ENTITY rel2.releng "<symbol xmlns='http://docbook.org/ns/docbook'>stable/9/</symbol>">
><!ENTITY rel2.relengdate "September 2011">
>]>
><book xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en">
>  <info>
>    <title>Frequently Asked Questions for &os;
>      &rel2.relx; and &rel.relx;</title>
>
>    <author><orgname>The &os; Documentation Project</orgname></author>
>
>    <copyright>
>      <year>1995</year>
>      <year>1996</year>
>      <year>1997</year>
>      <year>1998</year>
>      <year>1999</year>
>      <year>2000</year>
>      <year>2001</year>
>      <year>2002</year>
>      <year>2003</year>
>      <year>2004</year>
>      <year>2005</year>
>      <year>2006</year>
>      <year>2007</year>
>      <year>2008</year>
>      <year>2009</year>
>      <year>2010</year>
>      <year>2011</year>
>      <year>2012</year>
>      <year>2013</year>
>      <year>2014</year>
>      <year>2015</year>
>
>      <holder>The &os; Documentation Project</holder>
>    </copyright>
>
>    &legalnotice;
>
>    <legalnotice xml:id="trademarks" role="trademarks">
>      &tm-attrib.freebsd;
>      &tm-attrib.adobe;
>      &tm-attrib.ibm;
>      &tm-attrib.ieee;
>      &tm-attrib.intel;
>      &tm-attrib.linux;
>      &tm-attrib.microsoft;
>      &tm-attrib.netbsd;
>      &tm-attrib.opengroup;
>      &tm-attrib.sgi;
>      &tm-attrib.sun;
>      &tm-attrib.general;
>    </legalnotice>
>
>    <releaseinfo>$FreeBSD$</releaseinfo>
>
>    <abstract>
>      <para>This is the Frequently Asked Questions
>	<acronym>(FAQ)</acronym> for &os; versions
>	&rel2.relx; and &rel.relx;.  Every effort has been made to
>	make this <acronym>FAQ</acronym> as informative as possible;
>	if you have any suggestions as to how it may be improved, send
>	them to the &a.doc;.</para>
>
>      <para>The latest version of this document is always available
>	from the <link
>	  xlink:href="http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/faq/index.html">&os;
>	  website</link>.  It may also be downloaded as one large
>	<link xlink:href="book.html">HTML</link> file with HTTP or as
>	a variety of other formats from the <link
>	  xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/">&os; FTP
>	  server</link>.</para>
>    </abstract>
>  </info>
>
>  <chapter xml:id="introduction">
>    <title>Introduction</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="what-is-FreeBSD">
>	  <para>What is &os;?</para>
>	</question>
>
>	<answer>
>	  <para>&os; is a modern operating system for desktops,
>	    laptops, servers, and embedded systems with support for a
>	    large number of  <link
>	      xlink:href="http://www.FreeBSD.org/platforms/">platforms</link>.</para>
>
>	  <para>It is based on U.C. Berkeley's
>	    <quote>4.4BSD-Lite</quote> release, with some
>	    <quote>4.4BSD-Lite2</quote> enhancements.  It is also
>	    based indirectly on William Jolitz's port of U.C.
>	    Berkeley's <quote>Net/2</quote> to the &i386;, known as
>	    <quote>386BSD</quote>, though very little of the 386BSD
>	    code remains.</para>
>
>	  <para>&os; is used by companies, Internet Service Providers,
>	    researchers, computer professionals, students and home
>	    users all over the world in their work, education and
>	    recreation.</para>
>
>	  <para>For more detailed information on &os;, refer to the
>	    <link xlink:href="&url.books.handbook;/index.html">&os;
>	      Handbook</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="FreeBSD-goals">
>	  <para>What is the goal of the &os; Project?</para>
>	</question>
>
>	<answer>
>	  <para>The goal of the &os; Project is to provide a stable
>	    and fast general purpose operating system that may be used
>	    for any purpose without strings attached.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="bsd-license-restrictions">
>	  <para>Does the &os; license have any restrictions?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  Those restrictions do not control how the code
>	    is used, but how to treat the &os; Project itself.
>	    The license itself is available at
>	    <link
>	      xlink:href="http://www.FreeBSD.org/copyright/freebsd-license.html">license</link>
>	    and can be summarized like this:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>Do not claim that you wrote this.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Do not sue us if it breaks.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Do not remove or modify the license.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>Many of us have a significant investment in the
>	    project and would certainly not mind a little financial
>	    compensation now and then, but we definitely do not insist
>	    on it.  We believe that our first and foremost
>	    <quote>mission</quote> is to provide code to any and all
>	    comers, and for whatever purpose, so that the code gets
>	    the widest possible use and provides the widest possible
>	    benefit.  This, we believe, is one of the most fundamental
>	    goals of Free Software and one that we enthusiastically
>	    support.</para>
>
>	  <para>Code in our source tree which falls under the <link
>	      xlink:href="http://www.FreeBSD.org/copyright/COPYING">GNU
>	      General Public License (GPL)</link> or <link
>	      xlink:href="http://www.FreeBSD.org/copyright/COPYING.LIB">GNU
>	      Library General Public License (LGPL)</link> comes with
>	    slightly more strings attached, though at least on the
>	    side of enforced access rather than the usual opposite.
>	    Due to the additional complexities that can evolve in the
>	    commercial use of GPL software, we do, however, endeavor
>	    to replace such software with submissions under the more
>	    relaxed <link
>	      xlink:href="http://www.FreeBSD.org/copyright/freebsd-license.html">&os;
>	      license</link> whenever possible.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="replace-current-OS">
>	  <para>Can &os; replace my current operating system?</para>
>	</question>
>
>	<answer>
>	  <para>For most people, yes.  But this question is not quite
>	    that cut-and-dried.</para>
>
>	  <para>Most people do not actually use an operating system.
>	    They use applications.  The applications are what really
>	    use the operating system.  &os; is designed to provide a
>	    robust and full-featured environment for applications.  It
>	    supports a wide variety of web browsers, office suites,
>	    email readers, graphics programs, programming
>	    environments, network servers, and much more.
>	    Most of these applications can be
>	    managed through the <link
>	      xlink:href="http://www.FreeBSD.org/ports/">Ports
>	      Collection</link>.</para>
>
>	  <para>If an application is only available on one operating
>	    system, that operating system cannot just be replaced.
>	    Chances are, there is a very similar application on &os;,
>	    however.  As a solid office or Internet server or a
>	    reliable workstation, &os; will almost certainly do
>	    everything you need.  Many computer users across the
>	    world, including both novices and experienced &unix;
>	    administrators, use &os; as their only desktop operating
>	    system.</para>
>
>	  <para>Users migrating to &os; from another &unix;-like
>	    environment will find &os; to be similar.
>	    &windows; and &macos; users may be interested in instead
>	    using <link
>	      xlink:href="http://www.pcbsd.org/">PC-BSD</link>, a
>	    &os;-based desktop distribution.  Non-&unix; users should
>	    expect to invest some additional time learning the
>	    &unix; way of doing things.  This <acronym>FAQ</acronym>
>	    and the <link
>	      xlink:href="&url.books.handbook;/index.html">&os;
>	      Handbook</link> are excellent places to start.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="why-called-FreeBSD">
>	  <para>Why is it called &os;?</para>
>	</question>
>
>	<answer>
>	  <itemizedlist>
>	    <listitem>
>	      <para>It may be used free of charge, even by commercial
>		users.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Full source for the operating system is freely
>		available, and the minimum possible restrictions have
>		been placed upon its use, distribution and
>		incorporation into other work (commercial or
>		non-commercial).</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Anyone who has an improvement or bug fix is free
>		to submit their code and have it added to the source
>		tree (subject to one or two obvious
>		provisions).</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>It is worth pointing out that the word
>	    <quote>free</quote> is being used in two ways here: one
>	    meaning <quote>at no cost</quote> and the other meaning
>	    <quote>do whatever you like</quote>.  Apart from
>	    one or two things you <emphasis>cannot</emphasis> do with
>	    the &os; code, for example pretending you wrote it, you
>	    can really do whatever you like with it.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="differences-to-other-bsds">
>	  <para>What are the differences between &os; and NetBSD,
>	    OpenBSD, and other open source BSD operating
>	    systems?</para>
>	</question>
>
>	<answer>
>	  <para>James Howard wrote a good explanation of the history
>	    and differences between the various projects, called <link
>	      xlink:href="http://www.freebsdworld.gr/freebsd/bsd-family-tree.html">The
>	      BSD Family Tree</link> which goes a fair way to
>	    answering this question.  Some of the information is out
>	    of date, but the history portion in particular remains
>	    accurate.</para>
>
>	  <para>Most of the BSDs share patches and code, even today.
>	    All of the BSDs have common ancestry.</para>
>
>	  <para>The design goals of &os; are described in <xref
>	      linkend="FreeBSD-goals"/>, above.  The design goals of
>	    the other most popular BSDs may be summarized as
>	    follows:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>OpenBSD aims for operating system security above
>		all else.  The OpenBSD team wrote &man.ssh.1; and
>		&man.pf.4;, which have both been ported to
>		&os;.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>NetBSD aims to be easily ported to other hardware
>		platforms.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>DragonFly&nbsp;BSD is a fork of &os;&nbsp;4.8 that
>		has since developed many interesting features of its
>		own, including the HAMMER file system and support for
>		user-mode <quote>vkernels</quote>.</para>
>	    </listitem>
>	  </itemizedlist>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="latest-version">
>	  <para>What is the latest version of &os;?</para>
>	</question>
>
>	<answer>
>	  <para>At any point in the development of &os;, there can be
>	    multiple parallel branches.  &rel.relx; releases are made
>	    from the &rel.stable; branch, and &rel2.relx; releases are
>	    made from the &rel2.stable; branch.</para>
>
>	  <para>Up until the release of 9.0, the &rel2.relx; series
>	    was the one known as <emphasis>-STABLE</emphasis>.
>	    However, as of &rel.head.relx;, the &rel2.relx; branch
>	    will be designated for an <quote>extended support</quote>
>	    status and receive only fixes for major problems, such as
>	    security-related fixes.
>	    </para>
>
>	  <para>Version <link
>	      xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/i386/i386/&rel.current;-RELEASE/">&rel.current;</link>
>	    is the latest release from the &rel.stable; branch; it was
>	    released in &rel.current.date;.  Version <link
>	      xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/i386/&rel2.current;-RELEASE/">&rel2.current;</link>
>	    is the latest release from the &rel2.stable; branch; it
>	    was released in &rel2.current.date;.</para>
>
>	  <para>Releases are made <link linkend="release-freq">every
>	      few months</link>.  While many people stay more
>	    up-to-date with the &os; sources (see the questions on
>	    <link linkend="current">&os.current;</link> and <link
>	      linkend="stable">&os.stable;</link>) than that, doing so
>	    is more of a commitment, as the sources are a moving
>	    target.</para>
>
>	  <para>More information on &os; releases can be found on the
>	    <link
>	      xlink:href="http://www.FreeBSD.org/releng/index.html#release-build">Release
>	      Engineering page</link> and in &man.release.7;.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="current">
>	  <para>What is <emphasis>&os;-CURRENT</emphasis>?</para>
>	</question>
>
>	<answer>
>	  <para><link
>	      xlink:href="&url.books.handbook;/current-stable.html#current">&os.current;</link>
>	    is the development version of the operating system, which
>	    will in due course become the new &os.stable; branch.  As
>	    such, it is really only of interest to developers working
>	    on the system and die-hard hobbyists.  See the <link
>	      xlink:href="&url.books.handbook;/current-stable.html#current">relevant
>	      section</link> in the <link
>	      xlink:href="&url.books.handbook;/index.html">Handbook</link>
>	    for details on running
>	    <emphasis>-CURRENT</emphasis>.</para>
>
>	  <para>Users not familiar with &os; should not use
>	    &os.current;.  This branch sometimes evolves quite quickly
>	    and due to mistake can be un-buildable at times.  People
>	    that use &os.current; are expected to be able to analyze,
>	    debug, and report problems.</para>
>
>	  <para>&os; <link
>	      xlink:href="&url.base;/snapshots/">snapshot</link>
>	    releases are made based on the current state of the
>	    <emphasis>-CURRENT</emphasis> and
>	    <emphasis>-STABLE</emphasis> branches.  The goals behind
>	    each snapshot release are:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>To test the latest version of the installation
>		software.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>To give people who would like to run
>		<emphasis>-CURRENT</emphasis> or
>		<emphasis>-STABLE</emphasis> but who do not have the
>		time or bandwidth to follow it on a day-to-day basis
>		an easy way of bootstrapping it onto their
>		systems.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>To preserve a fixed reference point for the code
>		in question, just in case we break something really
>		badly later.  (Although Subversion normally prevents
>		anything horrible like this happening.)</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>To ensure that all new features and fixes in need
>		of testing have the greatest possible number of
>		potential testers.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>No claims are made that any
>	    <emphasis>-CURRENT</emphasis> snapshot can be considered
>	    <quote>production quality</quote> for any purpose.
>	    If a stable and fully tested system is needed,
>	    stick to full releases.</para>
>
>	  <para>Snapshot releases are directly available from <link
>	      xlink:href="&url.base;/snapshots/">snapshot</link>.</para>
>
>	  <para>Official snapshots are generated on a regular
>	    basis for all actively developed branches.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="stable">
>	  <para>What is the <emphasis>&os;-STABLE</emphasis>
>	    concept?</para>
>	</question>
>
>	<answer>
>	  <para>Back when &os;&nbsp;2.0.5 was released, &os;
>	    development branched in two.  One branch was named <link
>	      xlink:href="&url.books.handbook;/current-stable.html#stable">-STABLE</link>,
>	    one <link
>	      xlink:href="&url.books.handbook;/current-stable.html#current">-CURRENT</link>.
>	    <emphasis>&os;-STABLE</emphasis> is the development branch
>	    from which major releases are made.  Changes go into this
>	    branch at a slower pace and with the general assumption
>	    that they have first been tested in &os;-CURRENT.
>	    However, at any given time, the sources for &os;-STABLE
>	    may or may not be suitable for general use, as it may
>	    uncover bugs and corner cases that were not yet found in
>	    &os;-CURRENT.  Users who do not have the resources to
>	    perform testing should instead run the most recent release
>	    of &os;.
>	    <emphasis>&os;-CURRENT</emphasis>, on the other hand, has
>	    been one unbroken line since 2.0 was released, leading
>	    towards &rel.current;-RELEASE and beyond.  For more
>	    detailed information on branches see <quote><link
>	      xlink:href="&url.articles.releng;/release-proc.html#rel-branch">&os;
>	      Release Engineering: Creating the Release
>	      Branch</link></quote>, the status of the branches and
>	      the upcoming release schedule can be found on the <link
>	      xlink:href="http://www.FreeBSD.org/releng">Release
>	      Engineering Information</link> page.</para>
>
>	  <para>&rel.current;-STABLE is the actively developed
>	    <emphasis>-STABLE</emphasis> branch.  The latest release
>	    on the &rel.current;-STABLE branch is
>	    &rel.current;-RELEASE, which was released in
>	    &rel.current.date;.</para>
>
>	  <para>The &rel.head; branch is the actively developed
>	    <emphasis>-CURRENT</emphasis> branch toward the next
>	    generation of &os;.  See <link linkend="current">What is
>	    &os;-CURRENT?</link> for more information on this
>	    branch.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="release-freq">
>	  <para>When are &os; releases made?</para>
>	</question>
>
>	<answer>
>	  <para>The &a.re; releases a new major version of &os; about
>	    every 18 months and a new minor version about every 8
>	    months, on average.  Release dates are announced well in
>	    advance, so that the people working on the system know
>	    when their projects need to be finished and tested.  A
>	    testing period precedes each release, to ensure that the
>	    addition of new features does not compromise the stability
>	    of the release.  Many users regard this caution as one of
>	    the best things about &os;, even though waiting for all
>	    the latest goodies to reach <emphasis>-STABLE</emphasis>
>	    can be a little frustrating.</para>
>
>	  <para>More information on the release engineering process
>	    (including a schedule of upcoming releases) can be found
>	    on the <link
>	      xlink:href="http://www.FreeBSD.org/releng/index.html">release
>	      engineering</link> pages on the &os; Web site.</para>
>
>	  <para>For people who need or want a little more excitement,
>	    binary snapshots are made weekly as discussed
>	    above.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="responsible">
>	  <para>Who is responsible for &os;?</para>
>	</question>
>
>	<answer>
>	  <para>The key decisions concerning the &os; project, such as
>	    the overall direction of the project and who is allowed to
>	    add code to the source tree, are made by a <link
>	      xlink:href="&url.base;/administration.html#t-core">core
>	      team</link> of 9 people.  There is a much larger team of
>	    more than 350 <link
>	      xlink:href="&url.articles.contributors;/article.html#staff-committers">committers</link>
>	    who are authorized to make changes directly to the &os;
>	    source tree.</para>
>
>	  <para>However, most non-trivial changes are discussed in
>	    advance in the <link linkend="mailing">mailing
>	      lists</link>, and there are no restrictions on who may
>	    take part in the discussion.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="where-get">
>	  <para>Where can I get &os;?</para>
>	</question>
>
>	<answer>
>	  <para>Every significant release of &os; is available via
>	    anonymous FTP from the <link
>	      xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/"> &os;
>	      FTP site</link>:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>The latest &rel.stable; release,
>		&rel.current;-RELEASE can be found in the <link
>		  xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/i386/i386/&rel.current;-RELEASE/">&rel.current;-RELEASE
>		  directory</link>.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para><link
>		  xlink:href="&url.base;/snapshots/">Snapshot</link>
>		releases are made monthly for the <link
>		  linkend="current">-CURRENT</link> and <link
>		  linkend="stable">-STABLE</link> branch, these being
>		of service purely to bleeding-edge testers and
>		developers.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>The latest &rel2.stable; release,
>		&rel2.current;-RELEASE can be found in the <link
>		  xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/i386/&rel2.current;-RELEASE/">&rel2.current;-RELEASE
>		  directory</link>.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>Information about obtaining &os; on CD, DVD, and other
>	    media can be found in <link
>	      xlink:href="&url.books.handbook;/mirrors.html">the
>	      Handbook</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="access-pr">
>	  <para>How do I access the Problem Report database?</para>
>	</question>
>
>	<answer>
>	  <para>The Problem Report database of all user change
>	    requests may be queried by using our web-based PR <link
>	      xlink:href="https://bugs.FreeBSD.org/search/">query</link>
>	    interface.</para>
>
>	  <para>The <link
>	      xlink:href="&url.base;/support/bugreports.html">web-based
>	      problem report submission interface</link> can be used
>	    to submit problem reports through a web browser.</para>
>
>	  <para>Before submitting a problem report, read <link
>	      xlink:href="&url.articles.problem-reports;/article.html">Writing
>	      &os; Problem Reports</link>, an article on how to write
>	    good problem reports.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="support">
>    <title>Documentation and Support</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="books">
>	  <para>What good books are there about &os;?</para>
>	</question>
>
>	<answer>
>	  <para>The project produces a wide range of documentation,
>	    available online from this link: <uri
>	      xlink:href="http://www.FreeBSD.org/docs.html">http://www.FreeBSD.org/docs.html</uri>.
>	    In addition, <link
>	      linkend="bibliography">the Bibliography</link> at the
>	    end of this <acronym>FAQ</acronym>, and <link
>	      xlink:href="&url.books.handbook;/bibliography.html">the
>	      one in the Handbook</link> reference other recommended
>	    books.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="doc-formats">
>	  <para>Is the documentation available in other formats, such
>	    as plain text (ASCII), or &postscript;?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  The documentation is available in a number of
>	    different formats and compression schemes on the &os; FTP
>	    site, in the <link
>	      xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/">/pub/FreeBSD/doc/</link>
>	    directory.</para>
>
>	  <para>The documentation is categorized in a number of
>	    different ways.  These include:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>The document's name, such as
>		<literal>faq</literal>, or
>		<literal>handbook</literal>.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>The document's language and encoding.  These are
>		based on the locale names found under
>		<filename>/usr/share/locale</filename> on a &os;
>		system.  The current languages and encodings
>		are as follows:</para>
>
>	      <informaltable frame="none" pgwide="1">
>		<tgroup cols="2">
>		  <thead>
>		    <row>
>		      <entry>Name</entry>
>
>		      <entry>Meaning</entry>
>		    </row>
>		  </thead>
>
>		  <tbody>
>		    <row>
>		      <entry><literal>en_US.ISO8859-1</literal></entry>
>
>		      <entry>English (United States)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>bn_BD.ISO10646-1</literal></entry>
>
>		      <entry>Bengali or Bangla (Bangladesh)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>da_DK.ISO8859-1</literal></entry>
>
>		      <entry>Danish (Denmark)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>de_DE.ISO8859-1</literal></entry>
>
>		      <entry>German (Germany)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>el_GR.ISO8859-7</literal></entry>
>
>		      <entry>Greek (Greece)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>es_ES.ISO8859-1</literal></entry>
>
>		      <entry>Spanish (Spain)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>fr_FR.ISO8859-1</literal></entry>
>
>		      <entry>French (France)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>hu_HU.ISO8859-2</literal></entry>
>
>		      <entry>Hungarian (Hungary)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>it_IT.ISO8859-15</literal></entry>
>
>		      <entry>Italian (Italy)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>ja_JP.eucJP</literal></entry>
>
>		      <entry>Japanese (Japan, EUC encoding)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>mn_MN.UTF-8</literal></entry>
>
>		      <entry>Mongolian (Mongolia, UTF-8
>			encoding)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>nl_NL.ISO8859-1</literal></entry>
>
>		      <entry>Dutch (Netherlands)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>no_NO.ISO8859-1</literal></entry>
>
>		      <entry>Norwegian (Norway)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>pl_PL.ISO8859-2</literal></entry>
>
>		      <entry>Polish (Poland)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>pt_BR.ISO8859-1</literal></entry>
>
>		      <entry>Portuguese (Brazil)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>ru_RU.KOI8-R</literal></entry>
>
>		      <entry>Russian (Russia, KOI8-R encoding)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>sr_YU.ISO8859-2</literal></entry>
>
>		      <entry>Serbian (Serbia)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>tr_TR.ISO8859-9</literal></entry>
>
>		      <entry>Turkish (Turkey)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>zh_CN.UTF-8</literal></entry>
>
>		      <entry>Simplified Chinese (China, UTF-8
>			encoding)</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>zh_TW.UTF-8</literal></entry>
>
>		      <entry>Traditional Chinese (Taiwan, UTF-8
>			encoding)</entry>
>		    </row>
>		  </tbody>
>		</tgroup>
>	      </informaltable>
>
>	      <note>
>		<para>Some documents may not be available in all
>		  languages.</para>
>	      </note>
>	    </listitem>
>
>	    <listitem>
>	      <para>The document's format.  We produce the
>		documentation in a number of different output formats.
>		Each format has its own advantages and disadvantages.
>		Some formats are better suited for online reading,
>		while others are meant to be aesthetically pleasing
>		when printed on paper.  Having the documentation
>		available in any of these formats ensures that our
>		readers will be able to read the parts they are
>		interested in, either on their monitor, or on paper
>		after printing the documents.  The currently available
>		formats are:</para>
>
>	      <informaltable frame="none" pgwide="1">
>		<tgroup cols="2">
>		  <thead>
>		    <row>
>		      <entry>Format</entry>
>
>		      <entry>Meaning</entry>
>		    </row>
>		  </thead>
>
>		  <tbody>
>		    <row>
>		      <entry><literal>html-split</literal></entry>
>
>		      <entry>A collection of small, linked, HTML
>			files.</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>html</literal></entry>
>
>		      <entry>One large HTML file containing the entire
>			document</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>pdf</literal></entry>
>
>		      <entry>Adobe's Portable Document Format</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>ps</literal></entry>
>
>		      <entry>&postscript;</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>rtf</literal></entry>
>
>		      <entry>&microsoft;'s Rich Text Format</entry>
>		    </row>
>
>		    <row>
>		      <entry><literal>txt</literal></entry>
>
>		      <entry>Plain text</entry>
>		    </row>
>		  </tbody>
>		</tgroup>
>	      </informaltable>
>
>	      <note>
>		<para>Page numbers are not automatically updated when
>		  loading Rich Text Format into Word.  Press <keycombo
>		    action="simul"><keycap>Ctrl</keycap><keycap>A</keycap></keycombo>,
>		  <keycombo
>		    action="simul"><keycap>Ctrl</keycap><keycap>End</keycap></keycombo>,
>		  <keycap>F9</keycap> after loading the document, to
>		  update the page numbers.</para>
>	      </note>
>	    </listitem>
>
>	    <listitem>
>	      <para>The compression and packaging scheme.</para>
>
>	      <orderedlist>
>		<listitem>
>		  <para>Where the format is
>		    <literal>html-split</literal>, the files are
>		    bundled up using &man.tar.1;.  The resulting
>		    <filename>.tar</filename> file is then compressed
>		    using the compression schemes detailed in the next
>		    point.</para>
>		</listitem>
>
>		<listitem>
>		  <para>All the other formats generate one file.  For
>		    example,
>		    <filename>article.pdf</filename>,
>		    <filename>book.html</filename>, and so on.</para>
>
>		  <para>These files are then compressed using either
>		    the <literal>zip</literal> or
>		    <literal>bz2</literal> compression schemes.
>		    &man.tar.1; can be used to uncompress these
>		    files.</para>
>
>		  <para>So the &postscript; version of the Handbook,
>		    compressed using <literal>bzip2</literal> will be
>		    stored in a file called
>		    <filename>book.ps.bz2</filename> in the
>		    <filename>handbook/</filename> directory.</para>
>		</listitem>
>	      </orderedlist>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>After choosing the format and compression mechanism,
>	    download the
>	    compressed files, uncompress them, and then copy
>	    the appropriate documents into place.</para>
>
>	  <para>For example, the split HTML version of the
>	    <acronym>FAQ</acronym>, compressed using &man.bzip2.1;,
>	    can be found in
>	    <filename>doc/en_US.ISO8859-1/books/faq/book.html-split.tar.bz2</filename>
>	    To download and uncompress that file, type:</para>
>
>	  <screen>&prompt.root; <userinput>fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/en_US.ISO8859-1/books/faq/book.html-split.tar.bz2</userinput>
>&prompt.root; <userinput>tar xvf book.html-split.tar.bz2</userinput></screen>
>
>	  <para>If the file is compressed,
>	    <application>tar</application> will automatically
>	    detect the appropriate format and decompress it correctly,
>	    resulting in a collection of
>	    <filename>.html</filename> files.  The main one is called
>	    <filename>index.html</filename>, which will contain the
>	    table of contents, introductory material, and links to the
>	    other parts of the document.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="mailing">
>	  <para>Where do I find info on the &os; mailing lists?  What
>	    &os; news groups are available?</para>
>	</question>
>
>	<answer>
>	  <para>Refer to the <link
>	      xlink:href="&url.books.handbook;/eresources.html#eresources-mail">Handbook
>	      entry on mailing-lists</link> and the <link
>	      xlink:href="&url.books.handbook;/eresources-news.html">Handbook
>	      entry on newsgroups</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="irc">
>	  <para>Are there &os; IRC (Internet Relay Chat)
>	    channels?</para>
>	</question>
>
>	<answer>
>	  <para>Yes, most major IRC networks host a &os; chat
>	    channel:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>Channel <literal>#FreeBSDhelp</literal> on <link
>		  xlink:href="http://www.efnet.org/index.php">EFNet</link>
>		is a channel dedicated to helping &os; users.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Channel <literal>#FreeBSD</literal> on <link
>		  xlink:href="http://freenode.net/">Freenode</link> is
>		a general help channel with many users at any time.
>		The conversations have been known to run off-topic for
>		a while, but priority is given to users with &os;
>		questions.  Other users can help with
>		the basics, referring to the Handbook whenever
>		possible and providing links for learning more about
>		a particular topic.  This is primarily an English
>		speaking channel, though it does have users from all
>		over the world.  Non-native English speakers should
>		try to ask the question in English first and then
>		relocate to <literal>##freebsd-lang</literal> as
>		appropriate.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Channel <literal>#FreeBSD</literal> on <link
>		  xlink:href="http://www.dal.net/">DALNET</link> is
>		available at <systemitem>irc.dal.net</systemitem> in
>		the US and <systemitem>irc.eu.dal.net</systemitem> in
>		Europe.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Channel <literal>#FreeBSD</literal> on <link
>		  xlink:href="http://www.undernet.org/">UNDERNET</link>
>		is available at
>		<systemitem>us.undernet.org</systemitem> in the US and
>		<systemitem>eu.undernet.org</systemitem> in Europe.
>		Since it is a help channel, be prepared to read the
>		documents you are referred to.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Channel <literal>#FreeBSD</literal> on <link
>		  xlink:href="http://www.rusnet.org.ru/">RUSNET</link>
>		is a Russian language channel dedicated to
>		helping &os; users.  This is also good place for
>		non-technical discussions.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Channel <literal>#bsdchat</literal> on <link
>		  xlink:href="http://freenode.net/">Freenode</link> is
>		a Traditional Chinese (UTF-8 encoding) language
>		channel dedicated to helping &os; users.
>		This is also good place for non-technical
>		discussions.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>The &os; wiki has a <link
>	      xlink:href="http://wiki.freebsd.org/IrcChannels">good
>	      list</link> of IRC channels.</para>
>
>	  <para>Each of these channels are distinct and are not
>	    connected to each other.  Since their chat styles differ,
>	    try each to find one suited to your
>	    chat style.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="forums">
>	  <para>Are there any web based forums to discuss &os;?</para>
>	</question>
>	<answer>
>	  <para>The official &os; forums are located at <link
>	      xlink:href="https://forums.FreeBSD.org/">https://forums.FreeBSD.org/</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="training">
>	  <para>Where can I get commercial &os; training and
>	    support?</para>
>	</question>
>
>	<answer>
>	  <para><link xlink:href="http://www.ixsystems.com">iXsystems,
>	      Inc.</link>, parent company of the <link
>	      xlink:href="http://www.freebsdmall.com/">&os;
>	      Mall</link>, provides commercial &os; and PC-BSD
>	    software <link
>	      xlink:href="http://www.ixsystems.com/bsdsupport">support</link>,
>	    in addition to &os; development and tuning
>	    solutions.</para>
>
>	  <para>BSD Certification Group, Inc. provides system
>	    administration certifications for DragonFly&nbsp;BSD,
>	    &os;, NetBSD, and OpenBSD.  Refer to <link
>	      xlink:href="http://www.BSDCertification.org">their
>	      site</link> for more information.</para>
>
>	  <para>Any other organizations providing training and support
>	    should contact the Project to be listed here.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="install">
>    <info>
>      <title>Installation</title>
>
>      <author>
>	<personname>
>	  <firstname>Nik</firstname>
>	  <surname>Clayton</surname>
>	</personname>
>	<affiliation>
>	  <address>
>	    <email>nik@FreeBSD.org</email>
>	  </address>
>	</affiliation>
>      </author>
>    </info>
>
>    <qandaset>
>
>      <qandaentry>
>	<question xml:id="which-architecture">
>	  <para>Which platform should I download? I have a 64
>	    bit capable &intel; CPU,
>	    but I only see <literal>amd64</literal>.</para>
>	</question>
>
>	<answer>
>	  <para>&arch.amd64; is the term &os; uses for 64-bit
>	    compatible x86 architectures (also known as "x86-64" or
>	    "x64").  Most modern computers should use &arch.amd64;.
>	    Older hardware should use &arch.i386;.  When installing
>	    on a non-x86-compatible architecture, select the
>	    platform which best matches the hardware.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="floppy-download">
>	  <para>Which file do I download to get &os;?</para>
>	</question>
>
>	<answer>
>	  <para>On the <link
>	      xlink:href="http://www.freebsd.org/where.html">Getting
>	      &os;</link> page, select <literal>[iso]</literal> next
>	    to the architecture that matches the hardware.</para>
>
>	  <para>Any of the following can be used:</para>
>
>	  <informaltable frame="none" pgwide="1">
>	    <tgroup cols="2">
>	      <thead>
>		<row>
>		  <entry>file</entry>
>		  <entry>description</entry>
>		</row>
>	      </thead>
>
>	      <tbody>
>		<row>
>		  <entry><filename>disc1.iso</filename></entry>
>		  <entry>Contains enough to install &os; and
>		    a minimal set of packages.</entry>
>		</row>
>
>		<row>
>		  <entry><filename>dvd1.iso</filename></entry>
>		  <entry>Similar to <filename>disc1.iso</filename>
>		    but with additional packages.</entry>
>		</row>
>
>		<row>
>		  <entry><filename>memstick.img</filename></entry>
>		  <entry>A bootable image sufficient for writing to a
>		    USB stick.</entry>
>		</row>
>
>		<row>
>		  <entry><filename>bootonly.iso</filename></entry>
>		  <entry>A minimal image that requires network access
>		    during installation to completely install
>		    &os;.</entry>
>		</row>
>	      </tbody>
>	    </tgroup>
>	  </informaltable>
>
>	  <para>&arch.pc98; users require these floppy images:
>	    <filename>floppies/boot.flp</filename>,
>	    <filename>floppies/kern1.flp</filename>,
>	    <filename>floppies/kern2.flp</filename>, and
>	    <filename>floppies/mfsroot1.flp</filename>.  These images
>	    need to be written onto floppies by tools like
>	    &man.dd.1;.</para>
>
>	  <para>Full instructions on this procedure and a little bit
>	    more about installation issues in general can be found in
>	    the <link
>	      xlink:href="&url.books.handbook;/bsdinstall.html">Handbook
>	      entry on installing &os;</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="floppy-image-too-large">
>	  <para>What do I do if the install image does not
>	    boot?</para>
>	</question>
>
>	<answer>
>	  <para>This can be caused by not downloading the image in
>	    <emphasis>binary</emphasis> mode when using
>	    <acronym>FTP</acronym>.</para>
>
>	  <para>Some FTP clients default their transfer mode to
>	    <emphasis>ascii</emphasis> and attempt to change any
>	    end-of-line characters received to match the
>	    conventions used by the client's system.  This will
>	    almost invariably corrupt the boot image.  Check the
>	    SHA-256 checksum of the downloaded boot image: if it
>	    is not <emphasis>exactly</emphasis> that on the
>	    server, then the download process is suspect.</para>
>
>	  <para>When using a command line FTP client, type
>	    <emphasis>binary</emphasis> at the FTP command prompt
>	    after getting connected to the server and before
>	    starting the download of the image.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="install-instructions-location">
>	  <para>Where are the instructions for installing &os;?</para>
>	</question>
>
>	<answer>
>	  <para>Installation instructions
>	    can be found at <link
>	      xlink:href="&url.books.handbook;/bsdinstall.html">Handbook
>	      entry on installing &os;</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="need-to-run">
>	  <para>What are the minimum requirements to run &os;?</para>
>	</question>
>
>	<answer>
>	  <para>&os; requires a 486 or better PC,
>	    64&nbsp;MB or more of RAM, and at least 1.1 GB of hard
>	    disk space.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="custom-boot-floppy">
>	  <para>How can I make my own custom release or install
>	    disk?</para>
>	</question>
>
>	<answer>
>	  <para>Customized &os; installation media can be created by
>	    building a custom release.  Follow the instructions in the
>	    <link
>	      xlink:href="&url.articles.releng;/article.html">Release
>	      Engineering</link> article.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="windows-coexist">
>	  <para>Can &windows; co-exist with &os;?</para>
>	</question>
>
>	<answer>
>	  <para>If &windows; is installed first, then yes.  &os;'s
>	    boot manager will then manage to boot &windows; and &os;.
>	    If &windows; is installed afterwards, it will
>	    overwrite the boot manager.  If that
>	    happens, see the next section.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="bootmanager-restore">
>	  <para>Another operating system destroyed my Boot Manager.
>	    How do I get it back?</para>
>	</question>
>
>	<answer>
>	  <para>This depends upon the boot manager.
>	    The &os; boot selection menu can be reinstalled using
>	    &man.boot0cfg.8;.  For example, to restore the boot menu
>	    onto the disk <replaceable>ada0</replaceable>:</para>
>
>	  <screen>&prompt.root; <userinput>boot0cfg -B ada0</userinput></screen>
>
>	  <para>The non-interactive MBR bootloader can be installed
>	    using &man.gpart.8;:</para>
>
>	  <screen>&prompt.root; <userinput>gpart bootcode -b /boot/mbr ada0</userinput></screen>
>
>	  <para>For more complex situations, including GPT disks, see
>	    &man.gpart.8;.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="no-install-cdrom">
>	  <para>I booted from a CD, but the install program
>	    says no CD-ROM is found.  Where did it go?</para>
>	</question>
>
>	<answer>
>	  <para>The usual cause of this problem is a mis-configured
>	    CD-ROM drive.  Many PCs now ship with the CD-ROM as the
>	    slave device on the secondary IDE controller, with no
>	    master device on that controller.  This is illegal
>	    according to the ATAPI specification, but &windows; plays
>	    fast and loose with the specification, and the BIOS
>	    ignores it when booting.  This is why the BIOS was able to
>	    see the CD-ROM to boot from it, but why &os; cannot see it
>	    to complete the install.</para>
>
>	  <para>Reconfigure the system so that the CD-ROM is either
>	    the master device on the IDE controller it is attached to,
>	    or make sure that it is the slave on an IDE controller
>	    that also has a master device.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="need-complete-sources">
>	  <para>Do I need to install the source?</para>
>	</question>
>
>	<answer>
>	  <para>In general, no.  There is nothing in the base system
>	    which requires the presence of the source to operate.
>	    Some ports, like <package>sysutils/lsof</package>, will
>	    not build unless the source is installed.  In particular,
>	    if the port builds a kernel module or directly operates on
>	    kernel structures, the source must be installed.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="need-kernel">
>	  <para>Do I need to build a kernel?</para>
>	</question>
>
>	<answer>
>	  <para>Usually not.  The supplied <literal>GENERIC</literal>
>	    kernel contains the drivers an ordinary computer will
>	    need.  &man.freebsd-update.8;, the &os; binary upgrade
>	    tool, cannot upgrade custom kernels, another reason to
>	    stick with the <literal>GENERIC</literal> kernel when
>	    possible.  For computers with very limited RAM, such as
>	    embedded systems, it may be worthwhile to build a smaller
>	    custom kernel containing just the required drivers.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="password-encryption">
>	  <para>Should I use DES, Blowfish, or MD5 passwords and how
>	    do I specify which form my users receive?</para>
>	</question>
>
>	<answer>
>	  <para>&os;&nbsp;9 and later use
>	    <emphasis>SHA512</emphasis> by
>	    default.  DES
>	    passwords are still available for backwards compatibility
>	    with legacy operating systems which still
>	    use the less secure password format.  &os; also supports
>	    the Blowfish and MD5 password formats.  Which
>	    password format to use for new passwords is controlled by
>	    the <literal>passwd_format</literal> login capability in
>	    <filename>/etc/login.conf</filename>, which takes values
>	    of <literal>des</literal>, <literal>blf</literal> (if
>	    these are available) or <literal>md5</literal>.  See the
>	    &man.login.conf.5; manual page for more information about
>	    login capabilities.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ffs-limits">
>	  <para>What are the limits for FFS file systems?</para>
>	</question>
>
>	<answer>
>	  <para>For FFS file systems, the largest file system is
>	    practically limited by the amount of memory required to
>	    &man.fsck.8; the file system.  &man.fsck.8; requires one
>	    bit per fragment, which with the default fragment size of
>	    4&nbsp;KB equates to 32&nbsp;MB of memory per TB of disk.
>	    This does mean that on architectures which limit userland
>	    processes to 2&nbsp;GB (e.g., &i386;), the maximum
>	    &man.fsck.8;'able filesystem is ~60&nbsp;TB.</para>
>
>	  <para>If there was not a &man.fsck.8; memory limit the
>	    maximum filesystem size would be 2&nbsp;^&nbsp;64 (blocks)
>	    * 32&nbsp;KB => 16 Exa * 32&nbsp;KB => 512
>	    ZettaBytes.</para>
>
>	  <para>The maximum size of a single FFS file is approximately
>	    2&nbsp;PB with the default block size of 32&nbsp;KB.  Each
>	    32&nbsp;KB block can point to 4096 blocks.  With triple
>	    indirect blocks, the calculation is 32&nbsp;KB * 12 +
>	    32&nbsp;KB * 4096 + 32&nbsp;KB * 4096^2 + 32&nbsp;KB *
>	    4096^3.  Increasing the block size to 64&nbsp;KB will
>	    increase the max file size by a factor of 16.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="archsw-readin-failed-error">
>	  <para>Why do I get an error message, <errorname>readin
>	      failed</errorname> after compiling and booting a new
>	    kernel?</para>
>	</question>
>
>	<answer>
>	  <para>The world and kernel are out of sync.  This
>	    is not supported.  Be sure to use <command>make
>	      buildworld</command> and <command>make
>	      buildkernel</command> to update the kernel.</para>
>
>	  <para>Boot the system by specifying the kernel directly at
>	    the second stage, pressing any key when the
>	    <literal>|</literal> shows up before loader is
>	    started.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="general-configuration-tool">
>	  <para>Is there a tool to perform post-installation
>	    configuration tasks?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  <application>bsdconfig</application> provides a
>	    nice interface to configure &os; post-installation.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="hardware">
>    <title>Hardware Compatibility</title>
>
>    <sect1 xml:id="compatibility-general">
>      <title>General</title>
>
>      <qandaset>
>	<qandaentry>
>	  <question xml:id="which-hardware-to-get">
>	    <para>I want to get a piece of hardware for my &os;
>	      system.  Which model/brand/type is best?</para>
>	  </question>
>
>	  <answer>
>	    <para>This is discussed continually on the &os; mailing
>	      lists but is to be expected since hardware changes so
>	      quickly.  Read through the Hardware&nbsp;Notes
>	      for &os; <link
>		xlink:href="&rel.current.hardware;">&rel.current;</link>
>	      or <link
>		xlink:href="&rel2.current.hardware;">&rel2.current;</link>
>	      and search the mailing list <link
>		xlink:href="http://www.FreeBSD.org/search/#mailinglists">archives</link>
>	      before asking about the latest and greatest hardware.
>	      Chances are a discussion about that type of hardware
>	      took place just last week.</para>
>
>	    <para>Before purchasing a laptop, check the archives for
>	      &a.mobile; and &a.questions;, or possibly a specific
>	      mailing list for a particular hardware type.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="memory-upper-limitation">
>	    <para>What are the limits for memory? Does &os; support
>	      more than 4&nbsp;GB of memory
>	      (RAM)?  More than 16&nbsp;GB?  More than
>	      48&nbsp;GB?</para>
>	  </question>
>
>	  <answer>
>	    <para>&os; as an operating system generally supports
>	      as much physical memory (RAM) as the platform it is
>	      running on does.  Keep in mind that different platforms
>	      have different limits for memory; for example &i386;
>	      without <acronym>PAE</acronym> supports at most
>	      4&nbsp;GB of memory (and usually less than that because
>	      of PCI address space) and &i386; with PAE supports at
>	      most 64&nbsp;GB memory.  As of &os;&nbsp;10, AMD64
>	      platforms support up to 4&nbsp;TB of physical
>	      memory.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="memory-i386-over-4gb">
>	    <para>Why does &os; report less than 4&nbsp;GB memory when
>	      installed on an &i386; machine?</para>
>	  </question>
>
>	  <answer>
>	    <para>The total address space on &i386; machines is
>	      32-bit, meaning that at most 4&nbsp;GB of memory is
>	      addressable (can be accessed).  Furthermore, some
>	      addresses in this range are reserved by hardware for
>	      different purposes, for example for using and
>	      controlling PCI devices, for accessing video memory, and
>	      so on.  Therefore, the total amount of memory usable by
>	      the operating system for its kernel and applications is
>	      limited to significantly less than 4&nbsp;GB.  Usually,
>	      3.2&nbsp;GB to 3.7&nbsp;GB is the maximum usable
>	      physical memory in this configuration.</para>
>
>	    <para>To access more than 3.2&nbsp;GB to 3.7&nbsp;GB of
>	      installed memory (meaning up to 4&nbsp;GB but also more
>	      than 4&nbsp;GB), a special tweak called
>	      <acronym>PAE</acronym> must be used.  PAE stands for
>	      Physical Address Extension and is a way for 32-bit x86
>	      CPUs to address more than 4&nbsp;GB of memory.  It
>	      remaps the memory that would otherwise be overlaid by
>	      address reservations for hardware devices above the
>	      4&nbsp;GB range and uses it as additional physical
>	      memory (see &man.pae.4;).  Using PAE has some drawbacks;
>	      this mode of memory access is a little bit slower than
>	      the normal (without PAE) mode and loadable modules (see
>	      &man.kld.4;) are not supported.  This means all drivers
>	      must be compiled into the kernel.</para>
>
>	    <para>The most common way to enable PAE is to build a new
>	      kernel with the special ready-provided kernel
>	      configuration file called <filename>PAE</filename>,
>	      which is already configured to build a safe kernel.
>	      Note that some entries in this kernel configuration file
>	      are too conservative and some drivers marked as unready
>	      to be used with PAE are actually usable.  A rule of
>	      thumb is that if the driver is usable on 64-bit
>	      architectures (like AMD64), it is also usable with PAE.
>	      When creating a custom kernel configuration
>	      file, PAE can be enabled by adding the following
>	      line:</para>
>
>	    <programlisting>options       PAE</programlisting>
>
>	    <para>PAE is not much used nowadays because most new x86
>	      hardware also supports running in 64-bit mode, known as
>	      AMD64 or &intel;&nbsp;64.  It has a much larger address
>	      space and does not need such tweaks.  &os; supports
>	      AMD64 and it is recommended that this version of &os; be
>	      used instead of the &i386; version if 4&nbsp;GB or more
>	      memory is required.</para>
>	  </answer>
>	</qandaentry>
>      </qandaset>
>    </sect1>
>
>    <sect1 xml:id="compatibility-processors">
>      <title>Architectures and Processors</title>
>
>      <qandaset>
>	<qandaentry>
>	  <question xml:id="architectures">
>	    <para>Does &os; support architectures other than the
>	      x86?</para>
>	  </question>
>
>	  <answer>
>	    <para>Yes.  &os; divides support into multiple tiers.
>	      Tier 1 architectures, such as i386 or amd64; are fully
>	      supported.  Tiers 2 and 3 are supported on a
>	      best-effort basis.  A full explanation of the tier
>	      system is available in the <link
>		xlink:href="&url.articles.committers-guide;/archs.html">Committer's
>		Guide.</link></para>
>
>	    <para>A complete  list of supported architectures can be
>	      found on the <link
>		xlink:href="http://www.FreeBSD.org/platforms/">platforms
>		page.</link></para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="smp-support">
>	    <para>Does &os; support Symmetric Multiprocessing
>	      (SMP)?</para>
>	  </question>
>
>	  <answer>
>	    <para>&os; supports symmetric multi-processor (SMP) on all
>	      non-embedded platforms (e.g, &arch.i386;, &arch.amd64;,
>	      etc.).  SMP is also supported in arm and MIPS kernels,
>	      although some CPUs may not support this.  &os;'s SMP
>	      implementation uses fine-grained locking, and
>	      performance scales nearly linearly with number of
>	      CPUs.</para>
>
>	    <para>&man.smp.4; has more details.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="microcode">
>	    <para>What is microcode?
>	      How do I install &intel; CPU microcode updates?</para>
>	  </question>
>
>	  <answer>
>	    <para>Microcode is a method of programmatically
>	      implementing hardware level instructions.  This allows
>	      for CPU bugs to be fixed without replacing the on board
>	      chip.</para>
>
>	    <para>Install <package>sysutils/devcpu-data</package>,
>	      then add:</para>
>
>	    <programlisting>microcode_update_enable="YES"</programlisting>
>
>	    <para>to <filename>/etc/rc.conf</filename></para>
>	  </answer>
>	</qandaentry>
>      </qandaset>
>    </sect1>
>
>    <sect1 xml:id="compatibility-drives">
>      <title>Hard Drives, Tape Drives, and CD and DVD Drives</title>
>
>      <qandaset>
>	<qandaentry>
>	  <question xml:id="supported-hard-drives">
>	    <para>What kind of hard drives does &os; support?</para>
>	  </question>
>
>	  <answer>
>	    <para>&os; supports EIDE, SATA, SCSI, and SAS drives (with
>	      a compatible controller; see the next section), and all
>	      drives using the original <quote>Western Digital</quote>
>	      interface (MFM, RLL, ESDI, and of course IDE).  A few
>	      ESDI controllers that use proprietary interfaces may not
>	      work: stick to WD1002/3/6/7 interfaces and
>	      clones.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="supported-scsi-controllers">
>	    <para>Which SCSI or SAS controllers are supported?</para>
>	  </question>
>
>	  <answer>
>	    <para>See the complete list in the Hardware Notes for &os;
>	      <link
>		xlink:href="&rel.current.hardware;">&rel.current;</link>
>	      or <link
>		xlink:href="&rel2.current.hardware;">&rel2.current;</link>.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="tape-support">
>	    <para>What types of tape drives are supported?</para>
>	  </question>
>
>	  <answer>
>	    <para>&os; supports all standard SCSI tape
>	      interfaces.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="tape-changer-support">
>	    <para>Does &os; support tape changers?</para>
>	  </question>
>
>	  <answer>
>	    <para>&os; supports SCSI changers using the &man.ch.4;
>	      device and the &man.chio.1; command.  The details of how
>	      to control the changer can be found in
>	      &man.chio.1;.</para>
>
>	    <para>While
>	      <application>AMANDA</application> and some other
>	      products already understands changers, other
>	      applications only know how to move a tape from one point
>	      to another.  In this case, keep track of which slot a
>	      tape is in and which slot the tape currently in the
>	      drive needs to go back to.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="supported-cdrom-drives">
>	    <para>Which CD-ROM and CD-RW drives are supported by
>	      &os;?</para>
>	  </question>
>
>	  <answer>
>	    <para>Any SCSI drive connected to a supported controller
>	      is supported.  Most ATAPI compatible IDE CD-ROMs are
>	      supported.</para>
>
>	    <para>&os; supports any ATAPI-compatible IDE CD-R or CD-RW
>	      drive.  See &man.burncd.8; for details.</para>
>
>	    <para>&os; also supports any SCSI CD-R or CD-RW drives.
>	      Install the <package>sysutils/cdrtools</package> port or
>	      package, then use <command>cdrecord</command>.</para>
>	  </answer>
>	</qandaentry>
>      </qandaset>
>    </sect1>
>
>    <sect1 xml:id="compatibility-kbd-mice">
>      <title>Keyboards and Mice</title>
>
>      <qandaset>
>	<qandaentry>
>	  <question xml:id="moused">
>	    <para>Is it possible to use a mouse outside the
>	      X Window system?</para>
>	  </question>
>
>	  <answer>
>	    <para>The default console driver,
>	      &man.syscons.4;, provides the ability to use a mouse
>	      pointer in text consoles to cut &amp; paste text.  Run
>	      the mouse daemon, &man.moused.8;, and turn on the mouse
>	      pointer in the virtual console:</para>
>
>	    <screen>&prompt.root; <userinput>moused -p /dev/xxxx -t yyyy</userinput>
>&prompt.root; <userinput>vidcontrol -m on</userinput></screen>
>
>	    <para>Where <replaceable>xxxx</replaceable> is the mouse
>	      device name and <replaceable>yyyy</replaceable> is a
>	      protocol type for the mouse.  The mouse daemon can
>	      automatically determine the protocol type of most mice,
>	      except old serial mice.  Specify the
>	      <literal>auto</literal> protocol to invoke automatic
>	      detection.  If automatic detection does not work, see
>	      the &man.moused.8; manual page for a list of supported
>	      protocol types.</para>
>
>	    <para>For a PS/2 mouse, add
>	      <literal>moused_enable="YES"</literal> to
>	      <filename>/etc/rc.conf</filename> to start the mouse
>	      daemon at boot time.  Additionally, to
>	      use the mouse daemon on all virtual terminals instead of
>	      just the console, add <literal>allscreens_flags="-m
>		on"</literal> to
>	      <filename>/etc/rc.conf</filename>.</para>
>
>	    <para>When the mouse daemon is running, access to the
>	      mouse must be coordinated between the mouse daemon and
>	      other programs such as X Windows.  Refer to the
>	      <acronym>FAQ</acronym>
>	      <link linkend="x-and-moused">Why does my mouse not work
>		with X?</link> for more details on this issue.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="text-mode-cut-paste">
>	    <para>How do I cut and paste text with a mouse in the text
>	      console?</para>
>	  </question>
>
>	  <answer>
>	    <para>It is not possible to remove data using the mouse.
>	      However, it is possible to copy and paste.  Once the
>	      mouse daemon is running as described in the <link
>		linkend="moused">previous question</link>, hold down
>	      button 1 (left button) and move the mouse to select a
>	      region of text.  Then, press button 2 (middle button) to
>	      paste it at the text cursor.  Pressing button 3 (right
>	      button) will <quote>extend</quote> the selected region
>	      of text.</para>
>
>	    <para>If the mouse does not have a middle button, it is
>	      possible to emulate one or remap buttons using mouse
>	      daemon options.  See the &man.moused.8; manual page for
>	      details.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="mouse-wheel-buttons">
>	    <para>My mouse has a fancy wheel and buttons.  Can I use
>	      them in &os;?</para>
>	  </question>
>
>	  <answer>
>	    <para>The answer is, unfortunately, <quote>It
>		depends</quote>.  These mice with additional features
>	      require specialized driver in most cases.  Unless the
>	      mouse device driver or the user program has specific
>	      support for the mouse, it will act just like a standard
>	      two, or three button mouse.</para>
>
>	    <para>For the possible usage of wheels in the X Window
>	      environment, refer to <link
>		linkend="x-and-wheel">that section</link>.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="keyboard-delete-key">
>	    <para>How do I use my delete key in <command>sh</command>
>	      and <command>csh</command>?</para>
>	  </question>
>
>	  <answer>
>	    <para>For the <application>Bourne Shell</application>, add
>	      the following lines to <filename>~/.shrc</filename>.
>	      See &man.sh.1; and &man.editrc.5;.</para>
>
>	    <programlisting>bind ^? ed-delete-next-char # for console
>bind ^[[3~ ed-delete-next-char # for xterm</programlisting>
>
>	    <para>For the <application>C Shell</application>, add the
>	      following lines to <filename>~/.cshrc</filename>.
>	      See &man.csh.1;.</para>
>
>	    <programlisting>bindkey ^? delete-char # for console
>bindkey ^[[3~ delete-char # for xterm</programlisting>
>
>	    <para>For more information, see <link
>		xlink:href="http://www.ibb.net/~anne/keyboard.html">this
>		page</link>.</para>
>	  </answer>
>	</qandaentry>
>      </qandaset>
>    </sect1>
>
>    <sect1 xml:id="compatibility-other">
>      <title>Other Hardware</title>
>
>      <qandaset>
>	<qandaentry>
>	  <question xml:id="es1370-silent-pcm">
>	    <para>Workarounds for no sound from my &man.pcm.4; sound
>	      card?</para>
>	  </question>
>
>	  <answer>
>	    <para>Some sound cards set their output volume to 0 at
>	      every boot.  Run the following command every time the
>	      machine boots:</para>
>
>	    <screen>&prompt.root; <userinput>mixer pcm 100 vol 100 cd 100</userinput></screen>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="power-management-support">
>	    <para>Does &os; support power management on my
>	      laptop?</para>
>	  </question>
>
>	  <answer>
>	    <para>&os; supports the <acronym>ACPI</acronym> features
>	      found in modern hardware.  Further information can be
>	      found in &man.acpi.4;.</para>
>	  </answer>
>	</qandaentry>
>      </qandaset>
>    </sect1>
>  </chapter>
>
>  <chapter xml:id="troubleshoot">
>    <title>Troubleshooting</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="pae">
>	  <para>Why is &os; finding the wrong amount of memory on
>	    &i386; hardware?</para>
>	</question>
>
>	<answer>
>	  <para>The most likely reason is the difference between
>	    physical memory addresses and virtual addresses.</para>
>
>	  <para>The convention for most PC hardware is to use the
>	    memory area between 3.5&nbsp;GB and 4&nbsp;GB for a
>	    special purpose (usually for PCI).  This address space is
>	    used to access PCI hardware.  As a result real, physical
>	    memory cannot be accessed by that address space.</para>
>
>	  <para>What happens to the memory that should appear in that
>	    location is hardware dependent.  Unfortunately,
>	    some hardware does nothing and the ability to use that
>	    last 500&nbsp;MB of RAM is entirely lost.</para>
>
>	  <para>Luckily, most hardware remaps the memory to a higher
>	    location so that it can still be used.  However, this can
>	    cause some confusion when watching the boot
>	    messages.</para>
>
>	  <para>On a 32-bit version of &os;, the memory appears lost,
>	    since it will be remapped above 4&nbsp;GB, which a 32-bit
>	    kernel is unable to access.  In this case, the solution is
>	    to build a PAE enabled kernel.  See the entry on memory
>	    limits for more information.</para>
>
>	  <para>On a 64-bit version of &os;, or when running a
>	    PAE-enabled kernel, &os; will correctly detect and remap
>	    the memory so it is usable.  During boot, however, it may
>	    seem as if &os; is detecting more memory than the system
>	    really has, due to the described remapping.  This is
>	    normal and the available memory will be corrected as the
>	    boot process completes.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="signal11">
>	  <para>Why do my programs occasionally die with
>	    <errorname>Signal 11</errorname> errors?</para>
>	</question>
>
>	<answer>
>	  <para>Signal 11 errors are caused when a process has
>	    attempted to access memory which the operating system has
>	    not granted it access to.  If something like this is
>	    happening at seemingly random intervals,
>	    start investigating the cause.</para>
>
>	  <para>These problems can usually be attributed to
>	    either:</para>
>
>	  <orderedlist>
>	    <listitem>
>	      <para>If the problem is occurring only in a specific
>		custom application, it is
>		probably a bug in the code.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>If it is a problem with part of the base &os;
>		system, it may also be buggy code, but more often than
>		not these problems are found and fixed long before us
>		general <acronym>FAQ</acronym> readers get to use
>		these bits of code (that is what -CURRENT is
>		for).</para>
>	    </listitem>
>	  </orderedlist>
>
>	  <para>It is probably
>	    not a &os; bug if the
>	    problem occurs compiling a program, but the activity
>	    that the compiler is carrying out changes each
>	    time.</para>
>
>	  <para>For example, if <command>make
>	      buildworld</command> fails while trying
>	    to compile <filename>ls.c</filename> into
>	    <filename>ls.o</filename> and, when run again, it fails
>	    in the same place, this is a broken build.  Try
>	    updating source and try again.  If the compile fails
>	    elsewhere, it is almost certainly due to hardware.</para>
>
>	  <para>In the first case, use a debugger such as
>	    &man.gdb.1; to find the point in the program which is
>	    attempting to access a bogus address and fix
>	    it.</para>
>
>	  <para>In the second case, verify which piece of
>	    hardware is at fault.</para>
>
>	  <para>Common causes of this include:</para>
>
>	  <orderedlist>
>	    <listitem>
>	      <para>The hard disks might be overheating: Check that
>		the fans are still working, as the disk and
>		other hardware might be overheating.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>The processor running is overheating: This might
>		be because the processor has been overclocked, or the
>		fan on the processor might have died.  In either case,
>		ensure that the hardware is running at
>		what it is specified to run at, at least while trying
>		to solve this problem.  If it is not, clock it back
>		to the default settings.)</para>
>
>	      <para>Regarding overclocking, it is far
>		cheaper to have a slow system than a fried system that
>		needs replacing!  Also the community is not
>		sympathetic to problems on overclocked systems.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Dodgy memory: if multiple memory
>		SIMMS/DIMMS are installed, pull them all out and try
>		running the machine with each SIMM or DIMM
>		individually to narrow the problem down to either the
>		problematic DIMM/SIMM or perhaps even a
>		combination.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Over-optimistic motherboard settings: the BIOS
>		settings, and some motherboard jumpers, provide
>		options to set various timings.  The defaults
>		are often sufficient, but sometimes setting the wait
>		states on RAM too low, or setting the <quote>RAM
>		  Speed: Turbo</quote> option
>		will cause strange behavior.  A possible idea is to
>		set to BIOS defaults, after noting
>		the current settings first.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Unclean or insufficient power to the motherboard.
>		Remove any unused I/O boards, hard disks, or
>		CD-ROMs,
>		or disconnect the power cable from them, to see if
>		the power supply can manage a smaller load.  Or try
>		another power supply, preferably one with a little
>		more power.  For instance, if the current power supply
>		is rated at 250&nbsp;Watts, try one rated at
>		300&nbsp;Watts.</para>
>	    </listitem>
>	  </orderedlist>
>
>	  <para>Read the section on
>	    <link linkend="signal11">Signal 11</link> for a further
>	    explanation and a discussion on how memory testing
>	    software or hardware can still pass faulty memory.  There
>	    is an extensive <acronym>FAQ</acronym> on this at <link
>	      xlink:href="http://www.bitwizard.nl/sig11/">the SIG11
>	      problem <acronym>FAQ</acronym></link>.</para>
>
>	  <para>Finally, if none of this has helped, it is possibly
>	    a bug in &os;.
>	    Follow <link linkend="access-pr">these instructions</link>
>	    to send a problem report.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="trap-12-panic">
>	  <para>My system crashes with either <errorname>Fatal trap
>	      12: page fault in kernel mode</errorname>, or
>	    <errorname>panic:</errorname>, and spits out a bunch of
>	    information.  What should I do?</para>
>	</question>
>
>	<answer>
>	  <para>The &os; developers are interested in these
>	    errors, but need more information than just the error
>	    message.  Copy the full crash message.  Then consult the
>	    <acronym>FAQ</acronym> section on <link
>	      linkend="kernel-panic-troubleshooting">kernel
>	      panics</link>, build a debugging kernel, and get a
>	    backtrace.  This might sound difficult, but does not
>	    require any programming skills.  Just follow the
>	    instructions.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="proc-table-full">
>	  <para>What is the meaning of the error <errorname>maxproc
>	      limit exceeded by uid %i, please see tuning(7) and
>	      login.conf(5)</errorname>?</para>
>	</question>
>
>	<answer>
>	  <para>The &os; kernel will only allow a certain number of
>	    processes to exist at one time.  The number is based on
>	    the <varname>kern.maxusers</varname> &man.sysctl.8;
>	    variable.  <varname>kern.maxusers</varname> also affects
>	    various other in-kernel limits, such as network buffers.
>	    If the machine is heavily loaded,
>	    increase <varname>kern.maxusers</varname>.  This will
>	    increase these other system limits in addition to the
>	    maximum number of processes.</para>
>
>	  <para>To adjust the <varname>kern.maxusers</varname> value,
>	    see the <link
>	      xlink:href="&url.books.handbook;/configtuning-kernel-limits.html#kern-maxfiles">File/Process
>	      Limits</link> section of the Handbook.  While that
>	    section refers to open files, the same limits apply to
>	    processes.</para>
>
>	  <para>If the machine is lightly loaded but running a very
>	    large number of processes, adjust the
>	    <varname>kern.maxproc</varname> tunable by defining it in
>	    <filename>/boot/loader.conf</filename>.  The tunable will
>	    not get adjusted until the system is rebooted.  For more
>	    information about tuning tunables, see
>	    &man.loader.conf.5;.  If these processes are being run by
>	    a single user, adjust
>	    <varname>kern.maxprocperuid</varname> to be one less than
>	    the new <varname>kern.maxproc</varname> value.  It must
>	    be at least one less because one system program,
>	    &man.init.8;, must always be running.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="remote-fullscreen">
>	  <para>Why do full screen applications on remote machines
>	    misbehave?</para>
>	</question>
>
>	<answer>
>	  <para>The remote machine may be setting the terminal type to
>	    something other than <literal>xterm</literal> which is
>	    required by the &os; console.  Alternatively the kernel
>	    may have the wrong values for the width and height of the
>	    terminal.</para>
>
>	  <para>Check the value of the <envar>TERM</envar>
>	    environment variable is <literal>xterm</literal>.  If the
>	    remote machine does not support that try
>	    <literal>vt100</literal>.</para>
>
>	  <para>Run <command>stty -a</command> to check what the
>	    kernel thinks the terminal dimensions are.  If they are
>	    incorrect, they can be changed by running
>	    <command>stty rows <replaceable>RR</replaceable> cols
>	    <replaceable>CC</replaceable></command>.</para>
>
>	  <para>Alternatively, if the client machine has
>	    <package>x11/xterm</package> installed, then running
>	    <command>resize</command> will query the terminal for the
>	    correct dimensions and set them.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="connection-delay">
>	  <para>Why does it take so long to connect to my computer via
>	    <command>ssh</command> or
>	    <command>telnet</command>?</para>
>	</question>
>
>	<answer>
>	  <para>The symptom: there is a long delay between the time
>	    the TCP connection is established and the time when the
>	    client software asks for a password (or, in
>	    &man.telnet.1;'s case, when a login prompt
>	    appears).</para>
>
>	  <para>The problem: more likely than not, the delay is caused
>	    by the server software trying to resolve the client's IP
>	    address into a hostname.  Many servers, including the
>	    <application>Telnet</application> and
>	    <application>SSH</application> servers that come with
>	    &os;, do this to store the hostname in a log file for
>	    future reference by the administrator.</para>
>
>	  <para>The remedy: if the problem occurs whenever connecting
>	    the client computer to any server, the problem
>	    is with the client.  If the problem only occurs
>	    when someone connects to the server computer, the
>	    problem is with the server.</para>
>
>	  <para>If the problem is with the client, the only remedy is
>	    to fix the DNS so the server can resolve it.  If this is
>	    on a local network, consider it a server problem and keep
>	    reading.  If this is on the Internet,
>	    contact your ISP.</para>
>
>	  <para>If the problem is with the server on a
>	    local network, configure the server
>	    to resolve address-to-hostname queries for the local
>	    address range.  See &man.hosts.5; and &man.named.8;
>	    for more information.  If this is on the
>	    Internet, the problem may be that the local server's
>	    resolver is not functioning correctly.  To check, try to
>	    look up another host such as
>	    <systemitem>www.yahoo.com</systemitem>.  If it does not
>	    work, that is the problem.</para>
>
>	  <para>Following a fresh install of &os;, it is also possible
>	    that domain and name server information is missing from
>	    <filename>/etc/resolv.conf</filename>.  This will often
>	    cause a delay in <application>SSH</application>, as the
>	    option <literal>UseDNS</literal> is set to
>	    <literal>yes</literal> by default in
>	    <filename>/etc/ssh/sshd_config</filename>.  If this is
>	    causing the problem, either fill in the
>	    missing information in
>	    <filename>/etc/resolv.conf</filename> or set
>	    <literal>UseDNS</literal> to <literal>no</literal> in
>	    <filename>sshd_config</filename> as a temporary
>	    workaround.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="file-table-full">
>	  <para>Why does <errorname>file: table is full</errorname>
>	    show up repeatedly in &man.dmesg.8;?</para>
>	</question>
>
>	<answer>
>	  <para>This error message indicates that the number of
>	    available file descriptors have been exhausted on the
>	    system.  Refer to the <link
>	      xlink:href="&url.books.handbook;/configtuning-kernel-limits.html#kern-maxfiles">kern.maxfiles</link>
>	    section of the <link
>	      xlink:href="&url.books.handbook;/configtuning-kernel-limits.html">Tuning
>	      Kernel Limits</link> section of the Handbook for a
>	    discussion and solution.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="computer-clock-skew">
>	  <para>Why does the clock on my computer keep incorrect
>	    time?</para>
>	</question>
>
>	<answer>
>	  <para>The computer has two or more clocks, and &os; has
>	    chosen to use the wrong one.</para>
>
>	  <para>Run &man.dmesg.8;, and check for lines that contain
>	    <literal>Timecounter</literal>.  The one with the highest
>	    quality value that &os; chose.</para>
>
>	  <screen>&prompt.root; <userinput>dmesg | grep Timecounter</userinput>
>Timecounter "i8254" frequency 1193182 Hz quality 0
>Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
>Timecounter "TSC" frequency 2998570050 Hz quality 800
>Timecounters tick every 1.000 msec</screen>
>
>	  <para>Confirm this by checking the
>	    <varname>kern.timecounter.hardware</varname>
>	    &man.sysctl.3;.</para>
>
>	  <screen>&prompt.root; <userinput>sysctl kern.timecounter.hardware</userinput>
>kern.timecounter.hardware: ACPI-fast</screen>
>
>	  <para>It may be a broken ACPI timer.  The simplest solution
>	    is to disable the ACPI timer in
>	    <filename>/boot/loader.conf</filename>:</para>
>
>	  <programlisting>debug.acpi.disabled="timer"</programlisting>
>
>	  <para>Or the BIOS may modify the TSC clock&mdash;perhaps to
>	    change the speed of the processor when running from
>	    batteries, or going into a power saving mode, but &os; is
>	    unaware of these adjustments, and appears to gain or lose
>	    time.</para>
>
>	  <para>In this example, the <literal>i8254</literal> clock is
>	    also available, and can be selected by writing its name to
>	    the <varname>kern.timecounter.hardware</varname>
>	    &man.sysctl.3;.</para>
>
>	  <screen>&prompt.root; <userinput>sysctl kern.timecounter.hardware=i8254</userinput>
>kern.timecounter.hardware: TSC -&gt; i8254</screen>
>
>	  <para>The computer should now start keeping more accurate
>	    time.</para>
>
>	  <para>To have this change automatically run at boot time,
>	    add the following line to
>	    <filename>/etc/sysctl.conf</filename>:</para>
>
>	  <programlisting>kern.timecounter.hardware=i8254</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="indefinite-wait-buffer">
>	  <para>What does the error <errorname>swap_pager: indefinite
>	      wait buffer:</errorname> mean?</para>
>	</question>
>
>	<answer>
>	  <para>This means that a process is trying to page memory to
>	    disk, and the page attempt has hung trying to access the
>	    disk for more than 20 seconds.  It might be caused by bad
>	    blocks on the disk drive, disk wiring, cables, or any
>	    other disk I/O-related hardware.  If the drive itself is
>	    bad, disk errors will appear in
>	    <filename>/var/log/messages</filename> and in the output
>	    of <command>dmesg</command>.  Otherwise, check the cables
>	    and connections.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="lock-order-reversal">
>	  <para>What is a <errorname>lock order
>	      reversal</errorname>?</para>
>	</question>
>
>	<answer>
>	  <para>The &os; kernel uses a number of resource locks to
>	    arbitrate contention for certain resources.  When multiple
>	    kernel threads try to obtain multiple resource locks,
>	    there's always the potential for a deadlock, where two
>	    threads have each obtained one of the locks and blocks
>	    forever waiting for the other thread to release one of the
>	    other locks.  This sort of locking problem can be avoided
>	    if all threads obtain the locks in the same order.</para>
>
>	  <para>A run-time lock diagnostic system called
>	    &man.witness.4;, enabled in &os.current; and disabled by
>	    default for stable branches and releases, detects the
>	    potential for deadlocks due to locking errors, including
>	    errors caused by obtaining multiple resource locks with a
>	    different order from different parts of the kernel.  The
>	    &man.witness.4; framework tries to detect this problem as
>	    it happens, and reports it by printing a message to the
>	    system console about a <errorname>lock order
>	      reversal</errorname> (often referred to also as
>	    <acronym>LOR</acronym>).</para>
>
>	  <para>It is possible to get false positives, as
>	    &man.witness.4; is conservative.  A true positive report
>	    <emphasis>does not</emphasis> mean that a system is
>	    dead-locked; instead it should be understood as a warning
>	    that a deadlock could have happened here.</para>
>
>	  <note>
>	    <para>Problematic <acronym>LOR</acronym>s tend to get
>	      fixed quickly, so check the &a.current; before posting
>	      to it.</para>
>	  </note>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="called-with-non-sleepable-locks-held">
>	  <para>What does <errorname>Called ...  with the following
>	      non-sleepable locks held</errorname> mean?</para>
>	</question>
>
>	<answer>
>	  <para>This means that a function that may sleep was called
>	    while a mutex (or other unsleepable) lock was held.</para>
>
>	  <para>The reason this is an error is because mutexes are not
>	    intended to be held for long periods of time; they are
>	    supposed to only be held to maintain short periods of
>	    synchronization.  This programming contract allows device
>	    drivers to use mutexes to synchronize with the rest of the
>	    kernel during interrupts.  Interrupts (under &os;) may not
>	    sleep.  Hence it is imperative that no subsystem in the
>	    kernel block for an extended period while holding a
>	    mutex.</para>
>
>	  <para>To catch such errors, assertions may be added to the
>	    kernel that interact with the &man.witness.4; subsystem to
>	    emit a warning or fatal error (depending on the system
>	    configuration) when a potentially blocking call is made
>	    while holding a mutex.</para>
>
>	  <para>In summary, such warnings are non-fatal, however with
>	    unfortunate timing they could cause undesirable effects
>	    ranging from a minor blip in the system's responsiveness
>	    to a complete system lockup.</para>
>
>	  <para>For additional information about locking in &os; see
>	    &man.locking.9;.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="touch-not-found">
>	  <para>Why does
>	    <buildtarget>buildworld</buildtarget>/<buildtarget>installworld</buildtarget>
>	    die with the message <errorname>touch: not
>	      found</errorname>?</para>
>	</question>
>
>	<answer>
>	  <para>This error does not mean that the &man.touch.1;
>	    utility is missing.  The error is instead probably due to
>	    the dates of the files being set sometime in the future.
>	    If the CMOS clock is set to local time, run
>	    <command>adjkerntz&nbsp;-i</command> to adjust
>	    the kernel clock when booting into single-user
>	    mode.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="applications">
>    <title>User Applications</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="user-apps">
>	  <para>Where are all the user applications?</para>
>	</question>
>
>	<answer>
>	  <para>Refer to <link
>	      xlink:href="&url.base;/ports/index.html">the ports
>	      page</link> for info on software packages ported to
>	    &os;.  The list currently tops &os.numports; and is
>	    growing daily, so come back to check often or subscribe to
>	    the &a.announce; for periodic updates on new
>	    entries.</para>
>
>	  <para>Most ports should work on all supported versions of
>	    &os;.  Those that do not are specifically marked as such.
>	    Each time a &os; release is made, a snapshot of the ports
>	    tree at the time of release in also included in the
>	    <filename>ports/</filename> directory.</para>
>
>	  <para>&os; supports compressed binary packages to easily
>	    install and uninstall ports.  Use &man.pkg.7; to control
>	    the installation of packages.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="how-do-download-ports-tree">
>	  <para>How do I download the Ports tree? Should I be using
>	    SVN?</para>
>	</question>
>
>	<answer>
>	  <para>Any of the methods listed here work:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>Use portsnap for most use cases.  Refer to <link
>		  xlink:href="&url.books.handbook;/ports-using.html">Using
>		the Ports Collection</link> for instructions on how to
>		use this tool.</para>
>	    </listitem>
>	    <listitem>
>	      <para>Use SVN if custom patches to the
>		ports tree are needed.  Refer to <link
>		  xlink:href="&url.books.handbook;/svn.html">Using
>		  Subversion</link> for details.</para>
>	    </listitem>
>	    <listitem>
>	      <para>Use <acronym>CTM</acronym>, as described in <link
>		  xlink:href="&url.books.handbook;/ctm.html">Using
>		  <acronym>CTM</acronym></link> to receive patches by
>		email over an unreliable Internet connection.</para>
>	    </listitem>
>	  </itemizedlist>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="java">
>	  <para>Does &os; support &java;?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  Refer to <link
>	      xlink:href="&url.base;/java/index.html">http://www.FreeBSD.org/java/</link>
>	    for more information.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ports-4x">
>	  <para>Why can I not build this port on my
>	    &rel2.relx;&nbsp;-, or
>	    &rel.relx;&nbsp;-STABLE machine?</para>
>	</question>
>
>	<answer>
>	  <para>If the installed &os; version lags
>	    significantly behind <emphasis>-CURRENT</emphasis> or
>	    <emphasis>-STABLE</emphasis>, update the
>	    Ports Collection using the instructions in <link
>	      xlink:href="&url.books.handbook;/ports-using.html">Using
>	      the Ports Collection</link>.  If the system is
>	    up-to-date, someone might have committed a change to the
>	    port which works for <emphasis>-CURRENT</emphasis> but
>	    which broke the port for <emphasis>-STABLE</emphasis>.
>	    <link xlink:href="https://bugs.FreeBSD.org/submit/">Submit</link>
>	    a bug report, since the Ports Collection is supposed to
>	    work
>	    for both the <emphasis>-CURRENT</emphasis> and
>	    <emphasis>-STABLE</emphasis> branches.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="make-index">
>	  <para>I just tried to build <filename>INDEX</filename> using
>	    <command>make index</command>, and it failed.  Why?</para>
>	</question>
>
>	<answer>
>	  <para>First, make sure that the Ports Collection is
>	    up-to-date.  Errors that affect building
>	    <filename>INDEX</filename> from an up-to-date copy of the
>	    Ports Collection are high-visibility and are thus almost
>	    always fixed immediately.</para>
>
>	  <para>There are rare cases where <filename>INDEX</filename>
>	    will not build due to odd cases involving
>	    <varname>WITH_<replaceable>*</replaceable></varname> or
>	    <varname>WITHOUT_<replaceable>*</replaceable></varname>
>	    variables being set in <filename>make.conf</filename>.  If
>	    you suspect that this is the case, try to make
>	    <filename>INDEX</filename> with those make variables
>	    turned off before reporting it to &a.ports;.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ports-update">
>	  <para>I updated the sources, now how do I update my
>	    installed ports?</para>
>	</question>
>
>	<answer>
>	  <para>&os; does not include a port upgrading tool, but it
>	    does have some tools to make the upgrade process somewhat
>	    easier.  Additional tools are available to simplify
>	    port handling and are described the <link
>	      xlink:href="&url.books.handbook;/ports-using.html">Upgrading
>	      Ports</link> section in the &os; Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ports-major-upgrade">
>	  <para>Do I need to recompile every port each time I perform
>	    a major version update?</para>
>	</question>
>
>	<answer>
>	  <para>Yes!  While a recent system will run with
>	    software compiled under an older release,
>	    things will randomly crash and fail to work once
>	    other ports are installed or updated.</para>
>
>	  <para>When the system is upgraded, various shared libraries,
>	    loadable modules, and other parts of the system will be
>	    replaced with newer versions.  Applications linked against
>	    the older versions may fail to start or, in other cases,
>	    fail to function properly.</para>
>
>	  <para>For more information, see <link
>	      xlink:href="&url.books.handbook;/updating-upgrading-freebsdupdate.html#freebsdupdate-upgrade">the
>	      section on upgrades</link> in the &os; Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ports-minor-upgrade">
>	  <para>Do I need to recompile every port each time I perform
>	    a minor version update?</para>
>	</question>
>
>	<answer>
>	  <para>In general, no.  &os; developers do their utmost to
>	    guarantee binary compatibility across all releases with
>	    the same major version number.  Any exceptions will be
>	    documented in the Release Notes, and advice given there
>	    should be followed.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="minimal-sh">
>	  <para>Why is <command>/bin/sh</command> so minimal?  Why
>	    does &os; not use <command>bash</command> or another
>	    shell?</para>
>	</question>
>
>	<answer>
>	  <para>Many people need to write shell scripts which will be
>	    portable across many systems.  That is why &posix;
>	    specifies the shell and utility commands in great detail.
>	    Most scripts are written in Bourne shell (&man.sh.1;), and
>	    because several important programming interfaces
>	    (&man.make.1;, &man.system.3;, &man.popen.3;, and
>	    analogues in higher-level scripting languages like Perl
>	    and Tcl) are specified to use the Bourne shell to
>	    interpret commands.  Because the Bourne shell is so often
>	    and widely used, it is important for it to be quick to
>	    start, be deterministic in its behavior, and have a small
>	    memory footprint.</para>
>
>	  <para>The existing implementation is our best effort at
>	    meeting as many of these requirements simultaneously as we
>	    can.  To keep <command>/bin/sh</command> small, we have
>	    not provided many of the convenience features that other
>	    shells have.  That is why other more featureful shells
>	    like <command>bash</command>, <command>scsh</command>,
>	    &man.tcsh.1;, and <command>zsh</command> are available.
>	    Compare the memory utilization of
>	    these shells by looking at the <quote>VSZ</quote> and
>	    <quote>RSS</quote> columns in a <command>ps -u</command>
>	    listing.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="midi-sound-files">
>	  <para>How do I create audio CDs from my MIDI files?</para>
>	</question>
>
>	<answer>
>	  <para>To create audio CDs from MIDI files, first install
>	    <package>audio/timidity++</package> from ports then
>	    install manually the GUS patches set by Eric A. Welsh,
>	    available at <uri
>	      xlink:href="http://alleg.sourceforge.net/digmid.html">http://alleg.sourceforge.net/digmid.html</uri>.
>	    After <application>TiMidity++</application> has been
>	    installed properly, MIDI files may be converted to WAV
>	    files with the following command line:</para>
>
>	  <screen>&prompt.user; <userinput>timidity -Ow -s 44100 -o /tmp/juke/01.wav 01.mid</userinput></screen>
>
>	  <para>The WAV files can then be converted to other formats
>	    or burned onto audio CDs, as described in the <link
>	      xlink:href="&url.books.handbook;/creating-cds.html">&os;
>	      Handbook</link>.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="kernelconfig">
>    <title>Kernel Configuration</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="make-kernel">
>	  <para>I would like to customize my kernel.  Is it
>	    difficult?</para>
>	</question>
>
>	<answer>
>	  <para>Not at all!  Check out the <link
>	      xlink:href="&url.books.handbook;/kernelconfig.html">kernel
>	      config section of the Handbook</link>.</para>
>
>	  <note>
>	    <para>The new <filename>kernel</filename> will be
>	      installed to the <filename>/boot/kernel</filename>
>	      directory along with its modules, while the old kernel
>	      and its modules will be moved to the
>	      <filename>/boot/kernel.old</filename> directory.  If
>	      a mistake is made in the
>	      configuration, simply boot the previous version of the
>	      kernel.</para>
>	  </note>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="why-kernel-big">
>	  <para>Why is my kernel so big?</para>
>	</question>
>
>	<answer>
>	  <para><literal>GENERIC</literal> kernels shipped with &os;
>	    are compiled in <emphasis>debug mode</emphasis>.
>	    Kernels built in debug mode contain debug data in
>	    separate files that are used for debugging.
>	    &os; releases prior to 11.0 store these debug files in
>	    the same directory as the kernel itself,
>	    <filename>/boot/kernel/</filename>.
>	    In &os; 11.0 and later the debug files are stored in
>	    <filename>/usr/lib/debug/boot/kernel/</filename>.
>	    Note that there will be little or no performance loss from
>	    running a debug kernel, and it is useful to keep one
>	    around in case of a system panic.</para>
>
>	  <para>When running low on disk space, there
>	    are different options to reduce the size of
>	    <filename>/boot/kernel/</filename> and
>	    <filename>/usr/lib/debug/</filename>.</para>
>
>	  <para>To not install the symbol files,
>	    make sure the following line exists in
>	    <filename>/etc/src.conf</filename>:</para>
>
>	  <programlisting>WITHOUT_KERNEL_SYMBOLS=yes</programlisting>
>
>	  <para>For more information see &man.src.conf.5;.</para>
>
>	  <para>If you want to avoid building debug files altogether,
>	    make sure that both of the following are true:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>This line does not exist in the kernel
>		configuration file:</para>
>
>	      <programlisting>makeoptions DEBUG=-g</programlisting>
>	    </listitem>
>
>	    <listitem>
>	      <para>Do not run &man.config.8; with
>		<option>-g</option>.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>Either of the above settings will cause the kernel to
>	    be built in debug mode.</para>
>
>	  <para>To build and install only the specified modules, list
>	    them in
>	    <filename>/etc/make.conf</filename>:</para>
>
>	  <programlisting>MODULES_OVERRIDE= <replaceable>accf_http ipfw</replaceable></programlisting>
>
>	  <para>Replace <emphasis>accf_httpd ipfw</emphasis> with a
>	    list of needed modules.  Only the listed modules will be
>	    built.  This reduces the size of the kernel
>	    directory and decreases the amount of time needed to
>	    build the kernel.  For more information, read
>	    <filename>/usr/share/examples/etc/make.conf</filename>.</para>
>
>	  <para>Unneeded devices can be removed from the kernel
>	    to further reduce the size.  See <xref
>	      linkend="make-kernel"/> for more information.</para>
>
>	  <para>To put any of these options into effect, follow the
>	    instructions to <link
>	      xlink:href="&url.books.handbook;/kernelconfig-building.html">build
>	      and install</link> the new kernel.</para>
>
>	  <para>For reference, the &os; 11 &arch.amd64; kernel
>	    (<filename>/boot/kernel/kernel</filename>) is
>	    approximately 25&nbsp;MB.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="generic-kernel-build-failure">
>	  <para>Why does every kernel I try to build fail to compile,
>	    even <filename>GENERIC</filename>?</para>
>	</question>
>
>	<answer>
>	  <para>There are a number of possible causes for this
>	    problem:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>The source
>		tree is different from the one used to build the
>		currently running system.  When attempting an upgrade,
>		read <filename>/usr/src/UPDATING</filename>, paying
>		particular attention to the <quote>COMMON
>		  ITEMS</quote> section at the end.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>The <command>make
>		  buildkernel</command> command did not complete
>		  successfully.  The <command>make
>		  buildkernel</command> target relies on files
>		generated by the <command>make buildworld</command>
>		target to complete its job correctly.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Even when building <link
>		  linkend="stable">&os;-STABLE</link>, it is possible
>		that the source tree was fetched at a time when it was
>		either being modified or it was broken.
>		Only releases are guaranteed to be
>		buildable, although <link
>		  linkend="stable">&os;-STABLE</link> builds fine the
>		majority of the time.  Try re-fetching the source tree
>		and see if the problem goes away.  Try using a
>		different mirror in case the previous one is having
>		problems.</para>
>	    </listitem>
>	  </itemizedlist>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="scheduler-in-use">
>	  <para>Which scheduler is in use on a
>	    running system?</para>
>	</question>
>
>	<answer>
>	  <para>The name of the scheduler currently being used is
>	    directly available as the value of the
>	    <varname>kern.sched.name</varname> sysctl:</para>
>
>	  <screen>&prompt.user; sysctl <replaceable>kern.sched.name</replaceable>
>kern.sched.name: ULE</screen>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="scheduler-kern-quantum">
>	  <para>What is <varname>kern.sched.quantum</varname>?</para>
>	</question>
>
>	<answer>
>	  <para><varname>kern.sched.quantum</varname> is the maximum
>	    number of ticks a process can run without being preempted
>	    in the 4BSD scheduler.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="disks">
>    <title>Disks, File Systems, and Boot Loaders</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="adding-disks">
>	  <para>How can I add my new hard disk to my &os;
>	    system?</para>
>	</question>
>
>	<answer>
>	  <para>See the <link
>	      xlink:href="&url.books.handbook;/disks-adding.html">Adding
>	      Disks</link> section in the &os; Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="new-huge-disk">
>	  <para>How do I move my system over to my huge new
>	    disk?</para>
>	</question>
>
>	<answer>
>	  <para>The best way is to reinstall the operating system on
>	    the new disk, then move the user data over.  This is
>	    highly recommended when tracking
>	    <emphasis>-STABLE</emphasis> for more than one release or
>	    when updating a release instead of installing a new one.
>	    Install booteasy on both disks with &man.boot0cfg.8; and
>	    dual boot until you are happy with the new configuration.
>	    Skip the next paragraph to find out how to move the data
>	    after doing this.</para>
>
>	  <para>Alternatively, partition and label the new disk with
>	    either &man.sade.8; or &man.gpart.8;.  If the disks are
>	    MBR-formatted, booteasy can be installed on both disks
>	    with &man.boot0cfg.8; so that the computer can dual boot
>	    to the old or new system after the copying is done.</para>
>
>	  <para>Once the new disk set up,
>	    the data cannot just be copied.  Instead, use tools that
>	    understand device files and system flags, such as
>	    &man.dump.8;.  Although it is recommended
>	    to move the data while in single-user mode, it
>	    is not required.</para>
>
>	  <para>When the disks are formatted with
>	    <acronym>UFS</acronym>, never use anything but
>	    &man.dump.8; and &man.restore.8; to move the root file
>	    system.  These commands should also be used when moving a
>	    single partition to another empty partition.  The sequence
>	    of steps to use <command>dump</command> to move the data
>	    from one <acronym>UFS</acronym> partitions to a new
>	    partition is:</para>
>
>	  <procedure>
>	    <step>
>	      <para><command>newfs</command> the new partition.</para>
>	    </step>
>
>	    <step>
>	      <para><command>mount</command> it on a temporary mount
>		point.</para>
>	    </step>
>
>	    <step>
>	      <para><command>cd</command> to that directory.</para>
>	    </step>
>
>	    <step>
>	      <para><command>dump</command> the old partition, piping
>		output to the new one.</para>
>	    </step>
>	  </procedure>
>
>	  <para>For example, to move
>	    <filename>/dev/ada1s1a</filename> with
>	    <filename>/mnt</filename> as the temporary mount point,
>	    type:</para>
>
>	  <screen>&prompt.root; <userinput>newfs /dev/ada1s1a</userinput>
>&prompt.root; <userinput>mount /dev/ada1s1a /mnt</userinput>
>&prompt.root; <userinput>cd /mnt</userinput>
>&prompt.root; <userinput>dump 0af - / | restore rf -</userinput></screen>
>
>	  <para>Rearranging partitions with
>	    <command>dump</command> takes a bit more work.  To merge a
>	    partition like <filename>/var</filename> into its parent,
>	    create the new partition large enough for both, move the
>	    parent partition as described above, then move the child
>	    partition into the empty directory that the first move
>	    created:</para>
>
>	  <screen>&prompt.root; <userinput>newfs /dev/ada1s1a</userinput>
>&prompt.root; <userinput>mount /dev/ada1s1a /mnt</userinput>
>&prompt.root; <userinput>cd /mnt</userinput>
>&prompt.root; <userinput>dump 0af - / | restore rf -</userinput>
>&prompt.root; <userinput>cd var</userinput>
>&prompt.root; <userinput>dump 0af - /var | restore rf -</userinput></screen>
>
>	  <para>To split a directory from its parent, say putting
>	    <filename>/var</filename> on its own partition when it was
>	    not before, create both partitions, then mount the child
>	    partition on the appropriate directory in the temporary
>	    mount point, then move the old single partition:</para>
>
>	  <screen>&prompt.root; <userinput>newfs /dev/ada1s1a</userinput>
>&prompt.root; <userinput>newfs /dev/ada1s1d</userinput>
>&prompt.root; <userinput>mount /dev/ada1s1a /mnt</userinput>
>&prompt.root; <userinput>mkdir /mnt/var</userinput>
>&prompt.root; <userinput>mount /dev/ada1s1d /mnt/var</userinput>
>&prompt.root; <userinput>cd /mnt</userinput>
>&prompt.root; <userinput>dump 0af - / | restore rf -</userinput></screen>
>
>	  <para>The &man.cpio.1; and &man.pax.1; utilities are also
>	    available for moving user data.  These are known to lose
>	    file flag information, so use them with caution.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="safe-softupdates">
>	  <para>Which partitions can safely use Soft Updates?  I have
>	    heard that Soft Updates on <filename>/</filename> can
>	    cause problems.  What about Journaled Soft Updates?</para>
>	</question>
>
>	<answer>
>	  <para>Short answer: Soft Updates can usually be safely used
>	    on all partitions.</para>
>
>	  <para>Long answer:  Soft Updates has two characteristics
>	    that may be undesirable on certain partitions.  First, a
>	    Soft Updates partition has a small chance of losing data
>	    during a system crash.  The partition will not be
>	    corrupted as the data will simply be lost.  Second, Soft
>	    Updates can cause temporary space shortages.</para>
>
>	  <para>When using Soft Updates, the kernel can take up to
>	    thirty seconds to write changes to the physical disk.
>	    When a large file is deleted the file still resides on
>	    disk until the kernel actually performs the deletion.
>	    This can cause a very simple race condition.  Suppose
>	    one large file is deleted and another large file is
>	    immediately created.  The first large file is not yet
>	    actually removed from the physical disk, so the disk might
>	    not have enough room for the second large file.  This will
>	    produce an error that the partition does not have enough
>	    space, even though a large chunk of space has just been
>	    released.  A few seconds later, the file creation works as
>	    expected.</para>
>
>	  <para>If a system should crash after the kernel accepts a
>	    chunk of data for writing to disk, but before that data is
>	    actually written out, data could be lost.  This risk is
>	    extremely small, but generally manageable.</para>
>
>	  <para>These issues affect all partitions using Soft Updates.
>	    So, what does this mean for the root partition?</para>
>
>	  <para>Vital information on the root partition changes very
>	    rarely.  If the system crashed during the thirty-second
>	    window after such a change is made, it is possible that
>	    data could be lost.  This risk is negligible for most
>	    applications, but be aware that it exists.  If
>	    the system cannot tolerate this much risk, do not use
>	    Soft Updates on the root file system!</para>
>
>	  <para><filename>/</filename> is traditionally one of the
>	    smallest partitions.  If
>	    <filename>/tmp</filename> is on
>	    <filename>/</filename>, there may be intermittent
>	    space problems.  Symlinking <filename>/tmp</filename> to
>	    <filename>/var/tmp</filename> will solve this
>	    problem.</para>
>
>	  <para>Finally, &man.dump.8; does not work in live mode (-L)
>	    on a filesystem, with Journaled Soft Updates
>	    (<acronym>SU+J</acronym>).</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="mount-foreign-fs">
>	  <para>Can I mount other foreign file systems under
>	    &os;?</para>
>	</question>
>
>	<answer>
>	  <para>&os; supports a variety of other file systems.</para>
>
>	  <variablelist>
>	    <varlistentry>
>	      <term>UFS</term>
>
>	      <listitem>
>		<para>UFS CD-ROMs can be mounted directly on &os;.
>		  Mounting disk partitions from Digital UNIX and other
>		  systems that support UFS may be more complex,
>		  depending on the details of the disk partitioning
>		  for the operating system in question.</para>
>	      </listitem>
>	    </varlistentry>
>
>	    <varlistentry>
>	      <term>ext2/ext3</term>
>
>	      <listitem>
>		<para>&os; supports <literal>ext2fs</literal> and
>		  <literal>ext3fs</literal> partitions.  See
>		  &man.ext2fs.5; for more information.</para>
>	      </listitem>
>	    </varlistentry>
>
>	    <varlistentry>
>	      <term>NTFS</term>
>
>	      <listitem>
>		<para>FUSE based NTFS support is available as a port
>		  (<package>sysutils/fusefs-ntfs</package>).  For more
>		  information see <link
>		    xlink:href="http://www.tuxera.com/community/ntfs-3g-manual/"><application>ntfs-3g</application></link>.</para>
>	      </listitem>
>	    </varlistentry>
>
>	    <varlistentry>
>	      <term>FAT</term>
>
>	      <listitem>
>		<para>&os; includes a read-write FAT driver.  For more
>		  information, see &man.mount.msdosfs.8;.</para>
>	      </listitem>
>	    </varlistentry>
>
>	    <varlistentry>
>	      <term>ZFS</term>
>
>	      <listitem>
>		<para>&os; includes a port of &sun;'s ZFS driver.  The
>		  current recommendation is to use it only on
>		  &arch.amd64; platforms with sufficient memory.  For
>		  more information, see &man.zfs.8;.</para>
>	      </listitem>
>	    </varlistentry>
>	  </variablelist>
>
>	  <para>&os; includes the Network File System
>	    <acronym>NFS</acronym> and the &os; Ports Collection
>	    provides several FUSE applications to support many other
>	    file systems.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="mount-dos">
>	  <para>How do I mount a secondary DOS partition?</para>
>	</question>
>
>	<answer>
>	  <para>The secondary DOS partitions are found after
>	    <emphasis>all</emphasis> the primary partitions.  For
>	    example, if <literal>E</literal> is the
>	    second DOS partition on the second SCSI drive, there will
>	    be a device file for <quote>slice 5</quote> in
>	    <filename>/dev</filename>.  To mount it:</para>
>
>	  <screen>&prompt.root; <userinput>mount -t msdosfs /dev/da1s5 /dos/e</userinput></screen>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="crypto-file-system">
>	  <para>Is there a cryptographic file system for &os;?</para>
>	</question>
>
>	<answer>
>	  <para>Yes, &man.gbde.8; and &man.geli.8;.
>	    See the <link
>	      xlink:href="&url.books.handbook;/disks-encrypting.html">Encrypting
>	      Disk Partitions</link> section of the &os;
>	    Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="grub-loader">
>	  <para>How do I boot &os; and &linux; using
>	    <application>GRUB</application>?</para>
>	</question>
>
>	<answer>
>	  <para>To boot &os; using <application>GRUB</application>,
>	    add the following to either
>	    <filename>/boot/grub/menu.lst</filename> or
>	    <filename>/boot/grub/grub.conf</filename>, depending upon
>	    which is used by the &linux; distribution.</para>
>
>	  <programlisting>title &os; 9.1
>	root <replaceable>(hd0,a)</replaceable>
>	kernel /boot/loader</programlisting>
>
>	  <para>Where <replaceable>hd0,a</replaceable> points to the
>	    root partition on the first disk.  To specify
>	    the slice number, use something like this
>	    <replaceable>(hd0,2,a)</replaceable>.  By default, if the
>	    slice number is omitted, <application>GRUB</application>
>	    searches the first slice
>	    which has the <literal>a</literal> partition.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="booteasy-loader">
>	  <para>How do I boot &os; and &linux; using
>	    <application>BootEasy?</application></para>
>	</question>
>
>	<answer>
>	  <para>Install LILO at the start of the &linux; boot
>	    partition instead of in the Master Boot Record.  You can
>	    then boot LILO from
>	    <application>BootEasy</application>.</para>
>
>	  <para>This is recommended when running &windows; and &linux;
>	    as it makes it simpler to get &linux; booting again if
>	    &windows; is reinstalled.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="changing-bootprompt">
>	  <para>How do I change the boot prompt from
>	    <literal>???</literal> to something more
>	    meaningful?</para>
>	</question>
>
>	<answer>
>	  <para>This cannot be accomplished with the standard boot
>	    manager without rewriting it.  There are a number of other
>	    boot managers in the <filename>sysutils</filename>
>	    category of the Ports Collection.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="removable-drives">
>	  <para>How do I use a new removable drive?</para>
>	</question>
>
>	<answer>
>	  <para>If the drive already has a file system on it,
>	    use a command like this:</para>
>
>	  <screen>&prompt.root; <userinput>mount -t msdosfs /dev/da0s1 /mnt</userinput></screen>
>
>	  <para>If the drive will only be used with &os; systems,
>	    partition it with <acronym>UFS</acronym> or
>	    <acronym>ZFS</acronym>.  This will provide long filename
>	    support, improvement in performance, and stability.  If
>	    the drive will be used by other operating systems, a more
>	    portable choice, such as msdosfs, is better.</para>
>
>	  <screen>&prompt.root; <userinput>dd if=/dev/zero of=/dev/da0 count=2</userinput>
>&prompt.root; <userinput>gpart create -s GPT /dev/da0</userinput>
>&prompt.root; <userinput>gpart add -t freebsd-ufs /dev/da0</userinput></screen>
>
>	  <para>Finally, create a new file system:</para>
>
>	  <screen>&prompt.root; <userinput>newfs /dev/da0p1</userinput></screen>
>
>	  <para>and mount it:</para>
>
>	  <screen>&prompt.root; <userinput>mount /dev/da0s1 /mnt</userinput></screen>
>
>	  <para>It is a good idea to add a line to
>	    <filename>/etc/fstab</filename> (see &man.fstab.5;) so you
>	    can just type <command>mount /mnt</command> in the
>	    future:</para>
>
>	  <programlisting>/dev/da0p1 /mnt ufs rw,noauto 0 0</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="mount-cd-superblock">
>	  <para>Why do I get <errorname>Incorrect super
>	      block</errorname> when mounting a CD?</para>
>	</question>
>
>	<answer>
>	  <para>The type of device to mount must be specified.  This
>	    is described in the Handbook section on <link
>	      xlink:href="&url.books.handbook;/creating-cds.html#mounting-cd">Using
>	      Data CDs</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="cdrom-not-configured">
>	  <para>Why do I get <errorname>Device not
>	      configured</errorname> when mounting a CD?</para>
>	</question>
>
>	<answer>
>	  <para>This generally means that there is no CD in the
>	    drive, or the drive is not visible on the bus.
>	    Refer to the <link
>	      xlink:href="&url.books.handbook;/creating-cds.html#mounting-cd">Using
>	      Data CDs</link> section of the Handbook for a detailed
>	    discussion of this issue.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="cdrom-unicode-filenames">
>	  <para>Why do all non-English characters in filenames show up
>	    as <quote>?</quote> on my CDs when mounted in &os;?</para>
>	</question>
>
>	<answer>
>	  <para>The CD probably uses the <quote>Joliet</quote>
>	    extension for storing information about files and
>	    directories.  This is discussed in the Handbook section on
>	   <link
>	      xlink:href="&url.books.handbook;/creating-cds.html#mounting-cd">Using
>	      Data CD-ROMs</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="burncd-isofs">
>	  <para>A CD burned under &os; cannot be read
>	    under any other operating system.  Why?</para>
>	</question>
>
>	<answer>
>	  <para>This means a raw file was burned to the CD, rather
>	    than creating an ISO&nbsp;9660 file system.  Take a look
>	    at the Handbook section on <link
>	      xlink:href="&url.books.handbook;/creating-cds.html#mounting-cd">Using
>	      Data <acronym>CD</acronym>s</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="copy-cd">
>	  <para>How can I create an image of a data CD?</para>
>	</question>
>
>	<answer>
>	  <para>This is discussed in the Handbook section on <link
>	      xlink:href="&url.books.handbook;/creating-cds.html#mkisofs">Writing
>	      Data to an <acronym>ISO</acronym> File System</link>.
>	    For more on working with CD-ROMs, see the <link
>	      xlink:href="&url.books.handbook;/creating-cds.html">Creating
>	      CDs Section</link> in the Storage chapter in the
>	    Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="mount-audio-CD">
>	  <para>Why can I not <command>mount</command> an audio
>	    CD?</para>
>	</question>
>
>	<answer>
>	  <para>Trying to mount an audio CD will produce an error
>	    like <errorname>cd9660: /dev/acd0c: Invalid
>	      argument</errorname>.  This is because
>	    <command>mount</command> only works on file systems.
>	    Audio CDs do not have file systems; they just have data.
>	    Instead, use a program that reads audio CDs, such as the
>	    <package>audio/xmcd</package> package or port.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="multi-session-CD">
>	  <para>How do I <command>mount</command> a multi-session
>	    CD?</para>
>	</question>
>
>	<answer>
>	  <para>By default, &man.mount.8; will attempt to mount the
>	    last data track (session) of a CD.  To
>	    load an earlier session, use the
>	    <option>-s</option> command line argument.  Refer to
>	    &man.mount.cd9660.8; for specific examples.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="user-floppymount">
>	  <para>How do I let ordinary users mount CD-ROMs, DVDs,
>	    USB drives, and other removable media?</para>
>	</question>
>
>	<answer>
>	  <para>As <systemitem class="username">root</systemitem> set
>	    the sysctl variable <varname>vfs.usermount</varname> to
>	    <literal>1</literal>.</para>
>
>	  <screen>&prompt.root; <userinput>sysctl vfs.usermount=1</userinput></screen>
>
>	  <para>To make this persist across reboots, add the line
>	    <literal>vfs.usermount=1</literal> to
>	    <filename>/etc/sysctl.conf</filename> so that it is reset
>	    at system boot time.</para>
>
>	  <para>Users can only mount devices they have read
>	    permissions to.  To allow users to mount a device
>	    permissions must be set in
>	    <filename>/etc/devfs.conf</filename>.</para>
>
>	  <para>For example, to allow users to mount the first USB
>	    drive add:</para>
>
>	  <programlisting># Allow all users to mount a USB drive.
>	    own       /dev/da0       root:operator
>	    perm      /dev/da0       0666</programlisting>
>
>	  <para>All users can now mount devices they could read onto a
>	    directory that they own:</para>
>
>	  <screen>&prompt.user; <userinput>mkdir ~/my-mount-point</userinput>
>&prompt.user; <userinput>mount -t msdosfs /dev/da0 ~/my-mount-point</userinput></screen>
>
>	  <para>Unmounting the device is simple:</para>
>
>	  <screen>&prompt.user; <userinput>umount ~/my-mount-point</userinput></screen>
>
>	  <para>Enabling <varname>vfs.usermount</varname>, however,
>	    has negative security implications.  A better way to
>	    access &ms-dos; formatted media is to use the
>	    <package>emulators/mtools</package> package in the Ports
>	    Collection.</para>
>
>	  <note>
>	    <para>The device name used in the previous examples must
>	      be changed according to the configuration.</para>
>	  </note>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="du-vs-df">
>	  <para>The <command>du</command> and <command>df</command>
>	    commands show different amounts of disk space available.
>	    What is going on?</para>
>	</question>
>
>	<answer>
>	  <para>This is due to how these commands actually work.
>	    <command>du</command> goes through the directory tree,
>	    measures how large each file is, and presents the totals.
>	    <command>df</command> just asks the file system how much
>	    space it has left.  They seem to be the same thing, but a
>	    file without a directory entry will affect
>	    <command>df</command> but not
>	    <command>du</command>.</para>
>
>	  <para>When a program is using a file, and the file is
>	    deleted, the file is not really removed from the file
>	    system until the program stops using it.  The file is
>	    immediately deleted from the directory listing, however.
>	    As an example, consider a file large enough
>	    to affect the output of
>	    <command>du</command> and <command>df</command>.  A
>	    file being viewed with <command>more</command> can be
>	    deleted wihout causing an error.
>	    The entry is
>	    removed from the directory so no other program or user can
>	    access it.  However, <command>du</command> shows that it
>	    is gone as it has walked the directory tree and the
>	    file is not listed.  <command>df</command> shows that it
>	    is still there, as the file system knows that
>	    <command>more</command> is still using that space.  Once
>	    the <command>more</command> session ends,
>	    <command>du</command> and <command>df</command> will
>	    agree.</para>
>
>	  <para>This situation is common on web servers.  Many people
>	    set up a &os; web server and forget to rotate the log
>	    files.  The access log fills up <filename>/var</filename>.
>	    The new administrator deletes the file, but the system
>	    still complains that the partition is full.  Stopping and
>	    restarting the web server program would free the file,
>	    allowing the system to release the disk space.  To prevent
>	    this from happening, set up &man.newsyslog.8;.</para>
>
>	  <para>Note that Soft Updates can delay the freeing of disk
>	    space and it can take up to 30 seconds for the
>	    change to be visible.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="add-swap-space">
>	  <para>How can I add more swap space?</para>
>	</question>
>
>	<answer>
>	  <para>This section <link
>	      xlink:href="&url.books.handbook;/adding-swap-space.html">of the Handbook</link>
>	    describes how to do this.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="manufacturer-disk-size">
>	  <para>Why does &os; see my disk as smaller than the
>	    manufacturer says it is?</para>
>	</question>
>
>	<answer>
>	  <para>Disk manufacturers calculate gigabytes as a billion
>	    bytes each, whereas &os; calculates them as
>	    1,073,741,824&nbsp;bytes each.  This explains why, for
>	    example, &os;'s boot messages will report a disk that
>	    supposedly has 80&nbsp;GB as holding
>	    76,319&nbsp;MB.</para>
>
>	  <para>Also note that &os; will (by default) <link
>	      linkend="disk-more-than-full">reserve</link> 8% of the
>	    disk space.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="disk-more-than-full">
>	  <para>How is it possible for a partition to be more than
>	    100% full?</para>
>	</question>
>
>	<answer>
>	  <para>A portion of each UFS partition (8%, by default) is
>	    reserved for use by the operating system and the
>	    <systemitem class="username">root</systemitem> user.
>	    &man.df.1; does not count that space when calculating the
>	    <literal>Capacity</literal> column, so it can exceed 100%.
>	    Notice that the <literal>Blocks</literal>
>	    column is always greater than the sum of the
>	    <literal>Used</literal> and <literal>Avail</literal>
>	    columns, usually by a factor of 8%.</para>
>
>	  <para>For more details, look up <option>-m</option> in
>	    &man.tunefs.8;.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="slow-boot-memtest">
>	  <para>Why does &os; pause for a long time at boot when the
>	    system has large amounts of ram?</para>
>	</question>
>
>	<answer>
>	  <para>&os; 10.1 and earlier executes a memory test early
>	    in the boot process.
>	    When the system has a small amount of memory, the test
>	    takes a few seconds.  Computers with tens or hundreds of
>	    gigabytes of memory can take several minutes to complete
>	    the test.  The memory test can be disabled by adding
>	    <literal>hw.memtest.tests=0</literal> to
>	    <filename>/boot/loader.conf</filename>.</para>
>
>	  <para>For more details, see &man.loader.conf.5;.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="all-about-zfs">
>      <title>ZFS</title>
>
>      <qandaset>
>	<qandaentry>
>	  <question xml:id="how-much-ram-for-zfs">
>	    <para>What is the minimum amount of RAM one should have to
>	      run ZFS?</para>
>	  </question>
>
>	  <answer>
>	    <para>A minimum of 4GB of RAM is required for comfortable
>	      usage, but individual workloads can vary widely.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="what-is-zil">
>	    <para>What is the ZIL and when does it get used?</para>
>	  </question>
>
>	  <answer>
>	    <para>The <acronym>ZIL</acronym> (<acronym>ZFS</acronym>
>	      intent log) is a write log used to implement posix write
>	      commitment semantics across crashes.  Normally writes
>	      are bundled up into transaction groups and written to
>	      disk when filled (<quote>Transaction Group
>		Commit</quote>).  However syscalls like &man.fsync.2;
>	      require a commitment that the data is written to stable
>	      storage before returning.  The ZIL is needed for writes
>	      that have been acknowledged as written but which are not
>	      yet on disk as part of a transaction.  The transaction
>	      groups are timestamped.  In the event of a crash the
>	      last valid timestamp is found and missing data is merged
>	      in from the ZIL.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="need-ssd-for-zil">
>	    <para>Do I need a SSD for ZIL?</para>
>	  </question>
>
>	  <answer>
>	    <para>By default, ZFS stores the ZIL in the pool with all
>	      the data.  If an application has a heavy write load,
>	      storing the ZIL in a separate device that has very fast
>	      synchronous, sequential write performance can improve
>	      overall system.  For other workloads, a SSD is unlikely
>	      to make much of an improvement.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="what-is-l2arc">
>	    <para>What is the L2ARC?</para>
>	  </question>
>
>	  <answer>
>	    <para>The <acronym>L2ARC</acronym> is a read cache stored
>	      on a fast device such as an <acronym>SSD</acronym>.
>	      This cache is not persistent across reboots.  Note that
>	      RAM is used as the first layer of cache and the L2ARC is
>	      only needed if there is insufficient RAM.</para>
>
>	    <para>L2ARC needs space in the ARC to index it.  So,
>	      perversely, a working set that fits perfectly in the
>	      ARC will not fit perfectly any more if a L2ARC is used
>	      because part of the ARC is holding the L2ARC index,
>	      pushing part of the working set into the L2ARC which is
>	      slower than RAM.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="should-enable-dedup">
>	    <para>Is enabling deduplication advisable?</para>
>	  </question>
>
>	  <answer>
>	    <para>Generally speaking, no.</para>
>
>	    <para>Deduplication takes up a significant amount of RAM
>	      and may slow down read and write disk access times.
>	      Unless one is storing data that is very heavily
>	      duplicated, such as virtual machine images or user
>	      backups, it is possible that deduplication will do more
>	      harm than good.  Another consideration is the inability
>	      to revert deduplication status.  If data is written when
>	      deduplication is enabled, disabling dedup will not cause
>	      those blocks which were deduplicated to be replicated
>	      until they are next modified.</para>
>
>	    <para>Deduplication can also lead to some unexpected
>	      situations.  In particular, deleting files may become
>	      much slower.</para>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="zpool-fully-full">
>	    <para>I cannot delete or create files on my ZFS pool.
>	      How can I fix this?</para>
>	  </question>
>
>	  <answer>
>	    <para>This could happen because the pool is 100% full.
>	      ZFS requires space on the disk to write transaction
>	      metadata.  To restore the pool to a usable state,
>	      truncate the file to delete:</para>
>
>	    <screen>&prompt.user; <userinput>truncate -s 0 unimportant-file</userinput></screen>
>
>	    <para>File truncation works because a new transaction is
>	      not started, new spare blocks are created
>	      instead.</para>
>
>	    <note>
>	      <para>On systems with additional ZFS dataset tuning,
>		such as deduplication, the space may not be
>		immediately available</para>
>	    </note>
>	  </answer>
>	</qandaentry>
>
>	<qandaentry>
>	  <question xml:id="zfs-ssd-trim">
>	    <para>Does ZFS support TRIM for Solid State Drives?</para>
>	  </question>
>
>	  <answer>
>	    <para>ZFS TRIM support was added to &os;&nbsp;10-CURRENT
>	      with revision r<revnumber>240868</revnumber>.  ZFS TRIM
>	      support was added to all &os;-STABLE branches in
>	      r<revnumber>252162</revnumber> and
>	      r<revnumber>251419</revnumber>, respectively.</para>
>
>	    <para>ZFS TRIM is enabled by default, and can be turned
>	      off by adding this line to
>	      <filename>/etc/sysctl.conf</filename>:</para>
>
>	    <programlisting>vfs.zfs.trim_disable=1</programlisting>
>
>	    <note>
>	      <para>ZFS TRIM may not work with all configurations,
>		such as a ZFS filesystem on a GELI-backed
>		device.</para>
>	    </note>
>	  </answer>
>	</qandaentry>
>      </qandaset>
>  </chapter>
>
>  <chapter xml:id="admin">
>    <title>System Administration</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="startup-config-files">
>	  <para>Where are the system start-up configuration
>	    files?</para>
>	</question>
>
>	<answer>
>	  <para>The primary configuration file is
>	    <filename>/etc/defaults/rc.conf</filename> which is
>	    described in &man.rc.conf.5;.  System startup scripts
>	    such as <filename>/etc/rc</filename> and
>	    <filename>/etc/rc.d</filename>, which are described in
>	    &man.rc.8;, include this file.  <emphasis>Do not edit this
>	      file!</emphasis>  Instead, to edit an entry in
>	    <filename>/etc/defaults/rc.conf</filename>, copy the line
>	    into <filename>/etc/rc.conf</filename> and change it
>	    there.</para>
>
>	  <para>For example, if to start &man.named.8;, the
>	    included DNS server:</para>
>
>	  <screen>&prompt.root; <userinput>echo 'named_enable="YES"' &gt;&gt; /etc/rc.conf</userinput></screen>
>
>	  <para>To start up local services, place shell scripts in the
>	    <filename>/usr/local/etc/rc.d</filename> directory.  These
>	    shell scripts should be set executable, the default file
>	    mode is <literal>555</literal>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="adding-users">
>	  <para>How do I add a user easily?</para>
>	</question>
>
>	<answer>
>	  <para>Use the &man.adduser.8; command, or the &man.pw.8;
>	    command for more complicated situations.</para>
>
>	  <para>To remove the user, use the &man.rmuser.8; command or,
>	    if necessary, &man.pw.8;.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="root-not-found-cron-errors">
>	  <para>Why do I keep getting messages like <errorname>root:
>	      not found</errorname> after editing
>	    <filename>/etc/crontab</filename>?</para>
>	</question>
>
>	<answer>
>	  <para>This is normally caused by editing the system crontab.
>	    This is not the correct way to do things as the system
>	    crontab has a different format to the per-user crontabs.
>	    The system
>	    crontab has an extra field, specifying which user to run
>	    the command as.  &man.cron.8; assumes this user is the
>	    first word of the command to execute.  Since no such
>	    command exists, this error message is displayed.</para>
>
>	  <para>To delete the extra, incorrect crontab:</para>
>
>	  <screen>&prompt.root; <userinput>crontab -r</userinput></screen>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="su-wheel-group">
>	  <para>Why do I get the error, <errorname>you are not in the
>	      correct group to su root</errorname> when I try to
>	    <command>su</command> to <systemitem
>	      class="username">root</systemitem>?</para>
>	</question>
>
>	<answer>
>	  <para>This is a security feature.  In order to
>	    <command>su</command> to
>	    <systemitem class="username">root</systemitem>, or any
>	    other account with superuser privileges, the user account
>	    must be a member of the
>	    <systemitem class="groupname">wheel</systemitem> group.
>	    If this feature were not there, anybody with an
>	    account on a system who also found out <systemitem
>	      class="username">root</systemitem>'s password would be
>	    able to gain superuser level access to the system.</para>
>
>	  <para>To allow someone to <command>su</command> to
>	    <systemitem class="username">root</systemitem>, put
>	    them in the <systemitem
>	      class="groupname">wheel</systemitem> group using
>	    <command>pw</command>:</para>
>
>	  <screen>&prompt.root; <userinput>pw groupmod wheel -m lisa</userinput></screen>
>
>	  <para>The above example will add user <systemitem
>	      class="username">lisa</systemitem> to the group
>	    <systemitem class="groupname">wheel</systemitem>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="rcconf-readonly">
>	  <para>I made a mistake in <filename>rc.conf</filename>, or
>	    another startup file, and now I cannot edit it because the
>	    file system is read-only.  What should I do?</para>
>	</question>
>
>	<answer>
>	  <para>Restart the system using <userinput>boot
>	      -s</userinput> at the loader prompt to enter single-user
>	    mode.  When prompted for a shell pathname, press
>	    <keycap>Enter</keycap> and run <command>mount
>	      -urw /</command> to re-mount the root file system in
>	    read/write mode.  You may also need to run <command>mount
>	      -a -t ufs</command> to mount the file system where your
>	    favorite editor is defined.  If that editor is on
>	    a network file system, either configure
>	    the network manually before mounting the network file
>	    systems, or use an editor which resides on a local file
>	    system, such as &man.ed.1;.</para>
>
>	  <para>In order to use a full screen editor such as
>	    &man.vi.1; or &man.emacs.1;, run
>	    <command>export TERM=xterm</command> on &os; 9.0+
>	    so that these editors can load the correct data from the
>	    &man.termcap.5; database.</para>
>
>	  <para>After performing these steps, edit
>	    <filename>/etc/rc.conf</filename> to
>	    fix the syntax error.  The error message displayed
>	    immediately after the kernel boot messages should indicate
>	    the number of the line in the file which is at
>	    fault.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="printer-setup">
>	  <para>Why am I having trouble setting up my printer?</para>
>	</question>
>
>	<answer>
>	  <para>See the <link
>	      xlink:href="&url.books.handbook;/printing.html">Handbook
>	      entry on printing</link> for troubleshooting
>	      tips.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="keyboard-mappings">
>	  <para>How can I correct the keyboard mappings for my
>	    system?</para>
>	</question>
>
>	<answer>
>	  <para>Refer to the Handbook section on <link
>	      xlink:href="&url.books.handbook;/using-localization.html">using
>	      localization</link>, specifically the section on <link
>	      xlink:href="&url.books.handbook;/using-localization.html#setting-console">console
>	      setup</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="user-quotas">
>	  <para>Why can I not get user quotas to work properly?</para>
>	</question>
>
>	<answer>
>	  <orderedlist>
>	    <listitem>
>	      <para>It is possible that the kernel is not configured
>		to use quotas.  In this case,
>		add the following line to the kernel configuration
>		file and recompile the kernel:</para>
>
>	      <programlisting>options QUOTA</programlisting>
>
>	      <para>Refer to the <link
>		  xlink:href="&url.books.handbook;/quotas.html">Handbook
>		  entry on quotas</link> for full details.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Do not turn on quotas on
>		<filename>/</filename>.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Put the quota file on the file system that the
>		quotas are to be enforced on:</para>
>
>	      <informaltable frame="none" pgwide="1">
>		<tgroup cols="2">
>		  <thead>
>		    <row>
>		      <entry>File System</entry>
>
>		      <entry>Quota file</entry>
>		    </row>
>		  </thead>
>
>		  <tbody>
>		    <row>
>		      <entry><filename>/usr</filename></entry>
>
>		      <entry><filename>/usr/admin/quotas</filename></entry>
>		    </row>
>
>		    <row>
>		      <entry><filename>/home</filename></entry>
>
>		      <entry><filename>/home/admin/quotas</filename></entry>
>		    </row>
>
>		    <row>
>		      <entry>&hellip;</entry>
>
>		      <entry>&hellip;</entry>
>		    </row>
>		  </tbody>
>		</tgroup>
>	      </informaltable>
>	    </listitem>
>	  </orderedlist>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="sysv-ipc">
>	  <para>Does &os; support System V IPC primitives?</para>
>	</question>
>
>	<answer>
>	  <para>Yes, &os; supports System V-style IPC, including
>	    shared memory, messages and semaphores, in the
>	    <filename>GENERIC</filename> kernel.  With a custom
>	    kernel, support may be loaded with the
>	    <filename>sysvshm.ko</filename>,
>	    <filename>sysvsem.ko</filename> and
>	    <filename>sysvmsg.ko</filename> kernel modules, or
>	    enabled in the custom kernel by adding the following lines
>	    to the kernel configuration file:</para>
>
>	  <programlisting>options    SYSVSHM          # enable shared memory
>options    SYSVSEM          # enable for semaphores
>options    SYSVMSG          # enable for messaging</programlisting>
>
>	  <para>Recompile and install the kernel.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="sendmail-alternative">
>	  <para>What other mail-server software can I use instead of
>	    <application>Sendmail</application>?</para>
>	</question>
>
>	<answer>
>	  <para>The <link
>	      xlink:href="http://www.sendmail.org/"><application>Sendmail</application></link>
>	    server is the default mail-server software for &os;, but
>	    it can be replaced with another
>	    MTA installed from the Ports Collection.  Available ports
>	    include <package>mail/exim</package>,
>	    <package>mail/postfix</package>, and
>	    <package>mail/qmail</package>.  Search the mailing lists
>	    for discussions regarding the advantages and disadvantages
>	    of the available MTAs.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="forgot-root-pw">
>	  <para>I have forgotten the <systemitem
>	      class="username">root</systemitem> password!  What do I
>	    do?</para>
>	</question>
>
>	<answer>
>	  <para>Do not panic!  Restart the system, type
>	    <userinput>boot -s</userinput> at the
>	    <literal>Boot:</literal> prompt to enter single-user mode.
>	    At the question about the shell to use, hit
>	    <keycap>Enter</keycap> which will display a
>	    &prompt.root; prompt.  Enter <command>mount
>	      -urw /</command> to remount the root file system
>	    read/write, then run <command>mount -a</command> to
>	    remount all the file systems.  Run <command>passwd
>	      root</command> to change the <systemitem
>	      class="username">root</systemitem> password then run
>	    &man.exit.1; to continue booting.</para>
>
>	  <note>
>	    <para>If you are still prompted to give the <systemitem
>		class="username">root</systemitem> password when
>	      entering the single-user mode, it means that the console
>	      has been marked as <literal>insecure</literal> in
>	      <filename>/etc/ttys</filename>.  In this case, it will
>	      be required to boot from a &os; installation disk,
>	      choose the <guimenuitem>Live CD</guimenuitem> or
>	      <guimenuitem>Shell</guimenuitem> at the beginning of the
>	      install process and issue the commands mentioned above.
>	      Mount the specific partition in this
>	      case and then chroot to it.  For example, replace
>	      <command>mount -urw /</command> with
>	      <command>mount /dev/ada0p1 /mnt; chroot /mnt</command>
>	      for a system on
>	      <replaceable>ada0p1</replaceable>.</para>
>	  </note>
>
>	  <note>
>	    <para>If the root partition cannot be mounted from
>	      single-user mode, it is possible that the partitions are
>	      encrypted and it is impossible to mount them without the
>	      access keys.  For more information see the section
>	      about encrypted disks in the &os; <link
>		xlink:href="&url.books.handbook;/disks-encrypting.html">Handbook</link>.</para>
>	  </note>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="CAD-reboot">
>	  <para>How do I keep <keycombo
>	      action="simul"><keycap>Control</keycap><keycap>Alt</keycap><keycap>Delete</keycap></keycombo>
>	    from rebooting the system?</para>
>	</question>
>
>	<answer>
>	  <para>When using &man.syscons.4;, the default console
>	    driver, build and install a new kernel with this line in
>	    the configuration file:</para>
>
>	  <programlisting>options SC_DISABLE_REBOOT</programlisting>
>
>	  <para>This can also be done by setting the following
>	    &man.sysctl.8; which does not require a reboot or kernel
>	    recompile:</para>
>
>	  <screen>&prompt.root; <userinput>sysctl hw.syscons.kbd_reboot=0</userinput></screen>
>
>	  <note>
>	    <para>The above two methods are exclusive:  The
>	      &man.sysctl.8; does not exist if the kernel is compiled
>	      with <literal>SC_DISABLE_REBOOT</literal>.</para>
>	  </note>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="dos-to-unix-txt">
>	  <para>How do I reformat DOS text files to &unix;
>	    ones?</para>
>	</question>
>
>	<answer>
>	  <para>Use this &man.perl.1; command:</para>
>
>	  <screen>&prompt.user; <userinput>perl -i.bak -npe 's/\r\n/\n/g' file(s)</userinput></screen>
>
>	  <para>where <replaceable>file(s)</replaceable> is one or
>	    more files to process.  The modification is done in-place,
>	    with the original file stored with a
>	    <filename>.bak</filename> extension.</para>
>
>	  <para>Alternatively, use &man.tr.1;:</para>
>
>	  <screen>&prompt.user; <userinput>tr -d '\r' &lt; dos-text-file &gt; unix-file</userinput></screen>
>
>	  <para><replaceable>dos-text-file</replaceable> is the file
>	    containing DOS text while
>	    <replaceable>unix-file</replaceable> will contain the
>	    converted output.  This can be quite a bit faster than
>	    using <command>perl</command>.</para>
>
>	  <para>Yet another way to reformat DOS text files is to use
>	    the <package>converters/dosunix</package> port from the
>	    Ports Collection.  Consult its documentation about the
>	    details.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="reread-rc">
>	  <para>How do I re-read <filename>/etc/rc.conf</filename> and
>	    re-start <filename>/etc/rc</filename> without a
>	    reboot?</para>
>	</question>
>
>	<answer>
>	  <para>Go into single-user mode and then back to multi-user
>	    mode:</para>
>
>	  <screen>&prompt.root; <userinput>shutdown now</userinput>
>&prompt.root; <userinput>return</userinput>
>&prompt.root; <userinput>exit</userinput></screen>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="release-candidate">
>	  <para>I tried to update my system to the latest
>	    <emphasis>-STABLE</emphasis>, but got
>	    <emphasis>-BETA<replaceable>x</replaceable></emphasis>,
>	    <emphasis>-RC</emphasis> or
>	    <emphasis>-PRERELEASE</emphasis>!  What is going
>	    on?</para>
>	</question>
>
>	<answer>
>	  <para>Short answer: it is just a name.
>	    <emphasis>RC</emphasis> stands for <quote>Release
>	      Candidate</quote>.  It signifies that a release is
>	    imminent.  In &os;, <emphasis>-PRERELEASE</emphasis> is
>	    typically synonymous with the code freeze before a
>	    release.  (For some releases, the
>	    <emphasis>-BETA</emphasis> label was used in the same way
>	    as <emphasis>-PRERELEASE</emphasis>.)</para>
>
>	  <para>Long answer: &os; derives its releases from one of two
>	    places.  Major, dot-zero, releases, such as 9.0-RELEASE
>	    are branched from the head of the development stream,
>	    commonly referred to as <link
>	      linkend="current">-CURRENT</link>.  Minor releases, such
>	    as 6.3-RELEASE or 5.2-RELEASE, have been snapshots of the
>	    active <link linkend="stable">-STABLE</link> branch.
>	    Starting with 4.3-RELEASE, each release also now has its
>	    own branch which can be tracked by people requiring an
>	    extremely conservative rate of development (typically only
>	    security advisories).</para>
>
>	  <para>When a release is about to be made, the branch from
>	    which it will be derived from has to undergo a certain
>	    process.  Part of this process is a code freeze.  When a
>	    code freeze is initiated, the name of the branch is
>	    changed to reflect that it is about to become a release.
>	    For example, if the branch used to be called 6.2-STABLE,
>	    its name will be changed to 6.3-PRERELEASE to signify the
>	    code freeze and signify that extra pre-release testing
>	    should be happening.  Bug fixes can still be committed to
>	    be part of the release.  When the source code is in shape
>	    for the release the name will be changed to 6.3-RC to
>	    signify that a release is about to be made from it.  Once
>	    in the RC stage, only the most critical bugs found can be
>	    fixed.  Once the release (6.3-RELEASE in this example) and
>	    release branch have been made, the branch will be renamed
>	    to 6.3-STABLE.</para>
>
>	  <para>For more information on version numbers and the
>	    various Subversion branches, refer to the <link
>	      xlink:href="&url.articles.releng;/article.html">Release
>	      Engineering</link> article.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="kernel-chflag-failure">
>	  <para>I tried to install a new kernel, and the
>	    &man.chflags.1; failed.  How do I get around this?</para>
>	</question>
>
>	<answer>
>	  <para>Short answer: the security level is
>	    greater than 0.  Reboot directly to single-user mode to
>	    install the kernel.</para>
>
>	  <para>Long answer: &os; disallows changing system flags at
>	    security levels greater than 0.  To check the current
>	    security level:</para>
>
>	  <screen>&prompt.root; <userinput>sysctl kern.securelevel</userinput></screen>
>
>	  <para>The security level cannot be lowered in multi-user
>	    mode, so boot to single-user mode to install the kernel,
>	    or change the security level in
>	    <filename>/etc/rc.conf</filename> then reboot.  See the
>	    &man.init.8; manual page for details on
>	    <literal>securelevel</literal>, and see
>	    <filename>/etc/defaults/rc.conf</filename> and the
>	    &man.rc.conf.5; manual page for more information on
>	    <filename>rc.conf</filename>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="kernel-securelevel-time">
>	  <para>I cannot change the time on my system by more than one
>	    second!  How do I get around this?</para>
>	</question>
>
>	<answer>
>	  <para>Short answer: the system is at a security level
>	    greater than 1.  Reboot directly to single-user mode to
>	    change the date.</para>
>
>	  <para>Long answer: &os; disallows changing the time by more
>	    that one second at security levels greater than 1.  To
>	    check the security level:</para>
>
>	  <screen>&prompt.root; <userinput>sysctl kern.securelevel</userinput></screen>
>
>	  <para>The security level cannot be lowered in multi-user
>	    mode.  Either boot to single-user mode to change the date
>	    or change the security level in
>	    <filename>/etc/rc.conf</filename> and reboot.  See the
>	    &man.init.8; manual page for details on
>	    <literal>securelevel</literal>, and see
>	    <filename>/etc/defaults/rc.conf</filename> and the
>	    &man.rc.conf.5; manual page for more information on
>	    <filename>rc.conf</filename>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="statd-mem-leak">
>	  <para>Why is <command>rpc.statd</command> using 256&nbsp;MB
>	    of memory?</para>
>	</question>
>
>	<answer>
>	  <para>No, there is no memory leak, and it is not using
>	    256&nbsp;MB of memory.  For convenience,
>	    <command>rpc.statd</command> maps an obscene amount of
>	    memory into its address space.  There is nothing terribly
>	    wrong with this from a technical standpoint; it just
>	    throws off things like &man.top.1; and &man.ps.1;.</para>
>
>	  <para>&man.rpc.statd.8; maps its status file (resident on
>	    <filename>/var</filename>) into its address space; to save
>	    worrying about remapping it later when it needs to grow,
>	    it maps it with a generous size.  This is very evident
>	    from the source code, where one can see that the length
>	    argument to &man.mmap.2; is <literal>0x10000000</literal>,
>	    or one sixteenth of the address space on an IA32, or
>	    exactly 256&nbsp;MB.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="unsetting-schg">
>	  <para>Why can I not unset the <literal>schg</literal> file
>	    flag?</para>
>	</question>
>
>	<answer>
>	  <para>The system is running a securelevel greater than 0.
>	    Lower the securelevel and try again.  For
>	    more information, see <link linkend="securelevel">the <acronym>FAQ</acronym>
>	      entry on securelevel</link> and the &man.init.8; manual
>	    page.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="vnlru">
>	  <para>What is <literal>vnlru</literal>?</para>
>	</question>
>
>	<answer>
>	  <para><literal>vnlru</literal> flushes and frees vnodes when
>	    the system hits the <varname>kern.maxvnodes</varname>
>	    limit.  This kernel thread sits mostly idle, and only
>	    activates when there is a huge amount of RAM and users are
>	    accessing tens of thousands of tiny files.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="top-memory-states">
>	  <para>What do the various memory states displayed by
>	    <command>top</command> mean?</para>
>	</question>
>
>	
>	<answer>
>	  <itemizedlist>
>	    <listitem>
>	      <para><literal>Active</literal>: pages recently
>		statistically used.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para><literal>Inactive</literal>: pages recently
>		statistically unused.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para><literal>Cache</literal>: (most often) pages that
>		have percolated from inactive to a status where they
>		maintain their data, but can often be immediately
>		reused (either with their old association, or reused
>		with a new association).  There can be certain
>		immediate transitions from <literal>active</literal>
>		to <literal>cache</literal> state if the page is known
>		to be clean (unmodified), but that transition is a
>		matter of policy, depending upon the algorithm choice
>		of the VM system maintainer.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para><literal>Free</literal>: pages without data
>		content, and can be immediately used in certain
>		circumstances where cache pages might be ineligible.
>		Free pages can be reused at interrupt or process
>		state.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para><literal>Wired</literal>: pages that are fixed
>		into memory, usually for kernel purposes, but also
>		sometimes for special use in processes.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>Pages are most often written to disk (sort of a VM
>	    sync) when they are in the inactive state, but active
>	    pages can also be synced.  This depends upon the CPU
>	    tracking of the modified bit being available, and in
>	    certain situations there can be an advantage for a block
>	    of VM pages to be synced, whether they are active or
>	    inactive.  In most common cases, it is best to think of
>	    the inactive queue to be a queue of relatively unused
>	    pages that might or might not be in the process of being
>	    written to disk.  Cached pages are already synced, not
>	    mapped, but available for immediate process use with their
>	    old association or with a new association.  Free pages are
>	    available at interrupt level, but cached or free pages can
>	    be used at process state for reuse.  Cache pages are not
>	    adequately locked to be available at interrupt
>	    level.</para>
>
>	  <para>There are some other flags (e.g., busy flag or busy
>	    count) that might modify some of the described
>	    rules.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="free-memory-amount">
>	  <para>How much free memory is available?</para>
>	</question>
>
>	
>	<answer>
>	  <para>There are a couple of kinds of <quote>free
>	      memory</quote>.  One kind is the amount of memory
>	    immediately available without paging anything else out.
>	    That is approximately the size of cache queue + size of
>	    free queue (with a derating factor, depending upon system
>	    tuning).  Another kind of <quote>free memory</quote> is
>	    the total amount of <acronym>VM</acronym> space.  That can
>	    be complex, but is dependent upon the amount of swap space
>	    and memory.  Other kinds of <quote>free memory</quote>
>	    descriptions are also possible, but it is relatively
>	    useless to define these, but rather it is important to
>	    make sure that the paging rate is kept low, and to avoid
>	    running out of swap space.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="var-empty">
>	  <para>What is <filename>/var/empty</filename>?</para>
>	</question>
>
>	<answer>
>	  <para><filename>/var/empty</filename> is a directory that
>	    the &man.sshd.8; program uses when performing privilege
>	    separation.  The <filename>/var/empty</filename>
>	    directory is empty, owned by <systemitem
>	      class="username">root</systemitem> and has the
>	    <literal>schg</literal> flag set.  This directory should
>	    not be deleted.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="newsyslog-expectations">
>	  <para>I just changed
>	    <filename>/etc/newsyslog.conf</filename>.  How can I check
>	    if it does what I expect?</para>
>	</question>
>
>	<answer>
>	  <para>To see what &man.newsyslog.8; will do, use the
>	    following:</para>
>
>	  <screen>&prompt.user; <userinput>newsyslog -nrvv</userinput></screen>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="timezone">
>	  <para>My time is wrong, how can I change the
>	    timezone?</para>
>	</question>
>
>	<answer>
>	  <para>Use &man.tzsetup.8;.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="x">
>    <title>The X Window System and Virtual Consoles</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="whatis-X">
>	  <para>What is the X Window System?</para>
>	</question>
>
>	<answer>
>	  <para>The X Window System (commonly <literal>X11</literal>)
>	    is the most widely available windowing system capable of
>	    running on &unix; or &unix;&nbsp;like systems, including
>	    &os;.  <link xlink:href="http://www.x.org/wiki/">The X.Org
>	      Foundation</link> administers the <link
>	      xlink:href="http://en.wikipedia.org/wiki/X_Window_System_core_protocol">X
>	      protocol standards</link>, with the current reference
>	    implementation, version 11 release &xorg.version;, so
>	    references are often shortened to
>	    <literal>X11</literal>.</para>
>
>	  <para>Many implementations are available for different
>	    architectures and operating systems.  An implementation of
>	    the server-side code is properly known as an <literal>X
>	      server</literal>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="running-X">
>	  <para>I want to run &xorg;, how do I go about it?</para>
>	</question>
>
>	<answer>
>	  <para>To install &xorg; do one of the following:</para>
>
>	  <para>Use the <package>x11/xorg</package>
>	    meta-port, which builds and installs every &xorg;
>	    component.</para>
>
>	  <para>Use <package>x11/xorg-minimal</package>, which builds
>	    and installs only the necessary &xorg; components.</para>
>
>	  <para>Install &xorg; from &os; packages:</para>
>
>	  <screen><userinput>&prompt.root; pkg install xorg</userinput></screen>
>
>	  <para>After the installation of &xorg;, follow the
>	    instructions from the <link
>	      xlink:href="&url.books.handbook;/x-config.html">X11
>	      Configuration</link> section of the &os;
>	    Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="running-X-securelevels">
>	  <para>I <emphasis>tried</emphasis> to run X, but I get a
>	    <errorname>No devices detected.</errorname> error when I
>	    type <command>startx</command>.  What do I do now?</para>
>	</question>
>
>	<answer>
>	  <para>The system is probably running at a raised
>	    <literal>securelevel</literal>.  It is not possible to
>	    start X at a raised <literal>securelevel</literal> because
>	    X requires write access to &man.io.4;.  For more
>	    information, see at the &man.init.8; manual page.</para>
>
>	  <para>There are two solutions to the problem: set the
>	    <literal>securelevel</literal> back down to zero or run
>	    &man.xdm.1; (or an alternative display manager) at boot
>	    time before the <literal>securelevel</literal> is
>	    raised.</para>
>
>	  <para>See <xref linkend="xdm-boot"/> for more information
>	    about running &man.xdm.1; at boot time.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="x-and-moused">
>	  <para>Why does my mouse not work with X?</para>
>	</question>
>
>	<answer>
>	  <para>When using &man.syscons.4;, the default console
>	    driver, &os; can be configured to support a mouse pointer
>	    on each virtual screen.  To avoid conflicting with X,
>	    &man.syscons.4; supports a virtual device called
>	    <filename>/dev/sysmouse</filename>.  All mouse events
>	    received from the real mouse device are written to the
>	    &man.sysmouse.4; device via &man.moused.8;.  To use the
>	    mouse on one or more virtual consoles,
>	    <emphasis>and</emphasis> use X, see <xref
>	      linkend="moused" remap="another section"/> and set up
>	    &man.moused.8;.</para>
>
>	  <para>Then edit <filename>/etc/X11/xorg.conf</filename> and
>	    make sure the following lines exist:</para>
>
>	  <programlisting>Section "InputDevice"
>   Option          "Protocol" "SysMouse"
>   Option          "Device" "/dev/sysmouse"
>.....</programlisting>
>
>	  <para>Starting with &xorg; version 7.4, the
>	    <literal>InputDevice</literal> sections in
>	    <filename>xorg.conf</filename> are ignored in favor of
>	    autodetected devices.  To restore the old behavior, add
>	    the following line to the <literal>ServerLayout</literal>
>	    or <literal>ServerFlags</literal> section:</para>
>
>	  <programlisting>Option "AutoAddDevices" "false"</programlisting>
>
>	  <para>Some people prefer to use
>	    <filename>/dev/mouse</filename> under X.  To make this
>	    work, <filename>/dev/mouse</filename> should be linked
>	    to <filename>/dev/sysmouse</filename> (see
>	    &man.sysmouse.4;) by adding the following line to
>	    <filename>/etc/devfs.conf</filename> (see
>	    &man.devfs.conf.5;):</para>
>
>	  <programlisting>link    sysmouse    mouse</programlisting>
>
>	  <para>This link can be created by restarting &man.devfs.5;
>	    with the following command (as <systemitem
>	      class="username">root</systemitem>):</para>
>
>	  <screen>&prompt.root; <userinput>service devfs restart</userinput></screen>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="x-and-wheel">
>	  <para>My mouse has a fancy wheel.  Can I use it in X?</para>
>	</question>
>
>	<answer>
>	  <para>Yes, if X is configured for a 5 button mouse.  To
>	    do this, add the lines <literal>Buttons 5</literal>
>	    and <literal>ZAxisMapping 4 5</literal> to the
>	    <quote>InputDevice</quote> section of
>	    <filename>/etc/X11/xorg.conf</filename>, as seen in this
>	    example:</para>
>
>          <programlisting>Section "InputDevice"
>   Identifier      "Mouse1"
>   Driver          "mouse"
>   Option          "Protocol" "auto"
>   Option          "Device" "/dev/sysmouse"
>   Option          "Buttons" "5"
>   Option          "ZAxisMapping" "4 5"
>EndSection</programlisting>
>
>	    <para>To use the mouse in
>	      <application>Emacs</application>, also add the following
>	      lines to<filename>~/.emacs</filename>:</para>
>
>	    <programlisting>;; wheel mouse
>(global-set-key [mouse-4] 'scroll-down)
>(global-set-key [mouse-5] 'scroll-up)</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="x-and-synaptic">
>	  <para>My laptop has a Synaptics touchpad.  Can I use it in
>	    X?</para>
>	</question>
>
>	<answer>
>	  <para>Yes, after configuring a few things to make
>	    it work.</para>
>
>	  <para>In order to use the Xorg synaptics driver,
>	    first remove <literal>moused_enable</literal> from
>	    <filename>rc.conf</filename>.</para>
>
>	  <para>To enable synaptics, add the following line to
>	    <filename>/boot/loader.conf</filename>:</para>
>
>	  <programlisting>hw.psm.synaptics_support="1"</programlisting>
>
>	  <para>Add the following to
>	    <filename>/etc/X11/xorg.conf</filename>:</para>
>
>	  <programlisting>Section "InputDevice"
>Identifier  "Touchpad0"
>Driver      "synaptics"
>Option      "Protocol" "psm"
>Option      "Device" "/dev/psm0"
>EndSection</programlisting>
>
>	  <para>And be sure to add the following into the
>	    <quote>ServerLayout</quote> section:</para>
>
>	  <programlisting>InputDevice    "Touchpad0" "SendCoreEvents"</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="no-remote-x11">
>	  <para>How do I use remote X displays?</para>
>	</question>
>
>	<answer>
>	  <para>For security reasons, the default setting is to not
>	    allow a machine to remotely open a window.</para>
>
>	  <para>To enable this feature, start
>	    <application>X</application> with the optional
>	    <option>-listen_tcp</option> argument:</para>
>
>	  <screen>&prompt.user; <userinput>startx -listen_tcp</userinput></screen>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="virtual-console">
>	  <para>What is a virtual console and how do I make
>	    more?</para>
>	</question>
>
>	<answer>
>	  <para>Virtual consoles provide
>	    several simultaneous sessions on the same machine without
>	    doing anything complicated like setting up a network or
>	    running X.</para>
>
>	  <para>When the system starts, it will display a login prompt
>	    on the monitor after displaying all the boot messages.
>	    Type in your login name and password to
>	    start working on the first virtual
>	    console.</para>
>
>	  <para>To start another
>	    session, perhaps to look at documentation for a program
>	    or to read mail while waiting for an
>	    FTP transfer to finish,
>	    hold down <keycap>Alt</keycap> and press
>	    <keycap>F2</keycap>.  This will display the login prompt
>	    for the second virtual
>	      console.  To go back to the
>	    original session, press <keycombo
>	      action="simul"><keycap>Alt</keycap><keycap>F1</keycap></keycombo>.</para>
>
>	  <para>The default &os; installation has eight virtual
>	    consoles enabled.  <keycombo
>	      action="simul"><keycap>Alt</keycap><keycap>F1</keycap></keycombo>,
>	    <keycombo
>	      action="simul"><keycap>Alt</keycap><keycap>F2</keycap></keycombo>,
>	    <keycombo
>	      action="simul"><keycap>Alt</keycap><keycap>F3</keycap></keycombo>,
>	    and so on will switch between these virtual
>	    consoles.</para>
>
>	  <para>To enable more of virtual consoles, edit
>	    <filename>/etc/ttys</filename> (see &man.ttys.5;) and add
>	    entries for <filename>ttyv8</filename> to
>	    <filename>ttyvc</filename>, after the comment on
>	    <quote>Virtual terminals</quote>:</para>
>
>	  <programlisting># Edit the existing entry for ttyv8 in /etc/ttys and change
># "off" to "on".
>ttyv8   "/usr/libexec/getty Pc"         xterm  on secure
>ttyv9   "/usr/libexec/getty Pc"         xterm  on secure
>ttyva   "/usr/libexec/getty Pc"         xterm  on secure
>ttyvb   "/usr/libexec/getty Pc"         xterm  on secure</programlisting>
>
>	  <para>The more virtual
>	    terminals, the more resources that are used.  This can be
>	    problematic on systems with 8&nbsp;MB RAM or less.
>	    Consider changing <literal>secure</literal> to
>	    <literal>insecure</literal>.</para>
>
>	  <note>
>	    <para>Versions of &os; prior to 9.0 used the <quote>
>		cons25</quote> terminal type, and not <quote>
>		xterm</quote>.  Use the format of existing entries in
>	      when adding entries to
>	      <filename>/etc/ttys</filename>.</para>
>	  </note>
>
>	  <important>
>	    <para>In order to run an X server, at least one virtual
>	      terminal must be left to <literal>off</literal> for it
>	      to use.  This means that only eleven of the Alt-function
>	      keys can be used as virtual consoles so that one is left
>	      for the X server.</para>
>	  </important>
>
>	  <para>For example, to run X and eleven virtual consoles, the
>	    setting for virtual terminal 12 should be:</para>
>
>	  <programlisting>ttyvb   "/usr/libexec/getty Pc"         xterm  off secure</programlisting>
>
>	  <para>The easiest way to activate the
>	    virtual consoles is to reboot.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="vty-from-x">
>	  <para>How do I access the virtual consoles from X?</para>
>	</question>
>
>	<answer>
>	  <para>Use <keycombo
>	      action="simul"><keycap>Ctrl</keycap><keycap>Alt</keycap><keycap>F<replaceable>n</replaceable></keycap></keycombo>
>	    to switch back to a virtual console.  Press <keycombo
>	      action="simul"><keycap>Ctrl</keycap><keycap>Alt</keycap><keycap>F1</keycap></keycombo>
>	    to return to the first virtual console.</para>
>
>	  <para>Once at a text console, use
>	    <keycombo
>	      action="simul"><keycap>Alt</keycap><keycap>F<replaceable>n</replaceable></keycap></keycombo>
>	    to move between them.</para>
>
>	  <para>To return to the X session, switch to the
>	    virtual console running X.  If X was started from the
>	    command line using <command>startx</command>,
>	    the X session will attach to the next unused virtual
>	    console, not the text console from which it was invoked.
>	    For eight active virtual terminals, X will
>	    run on the ninth, so use <keycombo
>	      action="simul"><keycap>Alt</keycap><keycap>F9</keycap></keycombo>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="xdm-boot">
>	  <para>How do I start <application>XDM</application> on
>	    boot?</para>
>	</question>
>
>	<answer>
>	  <para>There are two schools of thought on how to start
>	    &man.xdm.1;.  One school starts <command>xdm</command>
>	    from <filename>/etc/ttys</filename> (see &man.ttys.5;)
>	    using the supplied example, while the other runs
>	    <command>xdm</command> from
>	    <filename>rc.local</filename> (see &man.rc.8;) or from an
>	    <filename>X</filename> script in
>	    <filename>/usr/local/etc/rc.d</filename>.  Both are
>	    equally valid, and one may work in situations where the
>	    other does not.  In both cases the result is the same: X
>	    will pop up a graphical login prompt.</para>
>
>	  <para>The &man.ttys.5; method has the advantage of
>	    documenting which vty X will start on and passing the
>	    responsibility of restarting the X server on logout to
>	    &man.init.8;.  The &man.rc.8; method makes it easy to
>	    <command>kill</command> <command>xdm</command> if there is
>	    a problem starting the X server.</para>
>
>	  <para>If loaded from &man.rc.8;, <command>xdm</command>
>	    should be started without any arguments.
>	    <command>xdm</command> must start
>	    <emphasis>after</emphasis> &man.getty.8; runs, or else
>	    <command>getty</command> and <command>xdm</command> will
>	    conflict, locking out the console.  The best way around
>	    this is to have the script sleep 10 seconds or so then
>	    launch <command>xdm</command>.</para>
>
>	  <para>When starting <command>xdm</command> from
>	    <filename>/etc/ttys</filename>, there still is a chance of
>	    conflict between <command>xdm</command> and &man.getty.8;.
>	    One way to avoid this is to add the <literal>vt</literal>
>	    number in
>	    <filename>/usr/local/lib/X11/xdm/Xservers</filename>:</para>
>
>	  <programlisting>:0 local /usr/local/bin/X vt4</programlisting>
>
>	  <para>The above example will direct the X server to run in
>	    <filename>/dev/ttyv3</filename>.  Note the number is
>	    offset by one.  The X server counts the vty from one,
>	    whereas the &os; kernel numbers the vty from zero.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="xconsole-failure">
>	  <para>Why do I get <errorname>Couldn't open
>	      console</errorname> when I run
>	    <command>xconsole</command>?</para>
>	</question>
>
>	<answer>
>	  <para>When <application>X</application> is started with
>	    <command>startx</command>, the permissions on
>	    <filename>/dev/console</filename> will
>	    <emphasis>not</emphasis> get changed, resulting in things
>	    like <command>xterm -C</command> and
>	    <command>xconsole</command> not working.</para>
>
>	  <para>This is because of the way console permissions are set
>	    by default.  On a multi-user system, one does not
>	    necessarily want just any user to be able to write on the
>	    system console.  For users who are logging directly onto a
>	    machine with a VTY, the &man.fbtab.5; file exists to solve
>	    such problems.</para>
>
>	  <para>In a nutshell, make sure an uncommented line of the
>	    form is in <filename>/etc/fbtab</filename> (see
>	    &man.fbtab.5;):</para>
>
>	  <programlisting>/dev/ttyv0 0600 /dev/console</programlisting>
>
>	  <para>It will ensure that whomever logs in on
>	    <filename>/dev/ttyv0</filename> will own the
>	    console.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ps2-x">
>	  <para>Why does my PS/2 mouse misbehave under X?</para>
>	</question>
>
>	<answer>
>	  <para>The mouse and the mouse driver may have become out of
>	    synchronization.  In rare cases, the driver may also
>	    erroneously report synchronization errors:</para>
>
>	  <programlisting>psmintr: out of sync (xxxx != yyyy)</programlisting>
>
>	  <para>If this happens, disable the synchronization check
>	    code by setting the driver flags for the PS/2 mouse driver
>	    to <literal>0x100</literal>.  This can be easiest achieved
>	    by adding <literal>hint.psm.0.flags="0x100"</literal> to
>	    <filename>/boot/loader.conf</filename> and
>	    rebooting.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="mouse-button-reverse">
>	  <para>How do I reverse the mouse buttons?</para>
>	</question>
>
>	<answer>
>	  <para>Type
>	    <command>xmodmap -e "pointer = 3 2 1"</command>.  Add this
>	    command to <filename>~/.xinitrc</filename> or
>	    <filename>~/.xsession</filename> to make it happen
>	    automatically.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="install-splash">
>	  <para>How do I install a splash screen and where do I find
>	    them?</para>
>	</question>
>
>	<answer>
>	  <para>The detailed answer for this question can be found in
>	    the <link
>	      xlink:href="&url.books.handbook;/boot-blocks.html#boot-splash">Boot
>	    Time Splash Screens</link> section of the &os;
>	    Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="windows-keys">
>	  <para>Can I use the <keycap>Windows</keycap> keys on my
>	    keyboard in X?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  Use &man.xmodmap.1; to
>	    define which functions the keys should perform.</para>
>
>	  <para>Assuming all Windows keyboards are
>	    standard, the keycodes for these three keys are the
>	    following:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para><keycode>115</keycode> &mdash;
>		<keycap>Windows</keycap> key, between the left-hand
>		<keycap>Ctrl</keycap> and <keycap>Alt</keycap>
>		keys</para>
>	    </listitem>
>
>	    <listitem>
>	      <para><keycode>116</keycode> &mdash;
>		<keycap>Windows</keycap> key, to the right of
>		<keycap>AltGr</keycap></para>
>	    </listitem>
>
>	    <listitem>
>	      <para><keycode>117</keycode> &mdash;
>		<keycap>Menu</keycap>, to the left of the right-hand
>		<keycap>Ctrl</keycap></para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>To have the left <keycap>Windows</keycap> key print a
>	    comma, try this.</para>
>
>	  <screen>&prompt.root; <userinput>xmodmap -e "keycode 115 = comma"</userinput></screen>
>
>	  <para>To have the <keycap>Windows</keycap> key-mappings
>	    enabled automatically every time X is started, either put
>	    the <command>xmodmap</command> commands in
>	    <filename>~/.xinitrc</filename> or, preferably, create
>	    a <filename>~/.xmodmaprc</filename> and include the
>	    <command>xmodmap</command> options, one per line, then add
>	    the following line to
>	    <filename>~/.xinitrc</filename>:</para>
>
>	  <programlisting>xmodmap $HOME/.xmodmaprc</programlisting>
>
>	  <para>For example, to map the 3 keys to be
>	    <keycap>F13</keycap>, <keycap>F14</keycap>, and
>	    <keycap>F15</keycap>, respectively.  This would make it
>	    easy to map them to useful functions within applications
>	    or the window manager.</para>
>
>	  <para>To do this, put the following in
>	    <filename>~/.xmodmaprc</filename>.</para>
>
>	  <programlisting>keycode 115 = F13
>keycode 116 = F14
>keycode 117 = F15</programlisting>
>
>	  <para>For the <package>x11-wm/fvwm2</package> desktop
>	    manager, one could map the keys so that
>	    <keycap>F13</keycap> iconifies or de-iconifies the
>	    window the cursor is in, <keycap>F14</keycap> brings the
>	    window the cursor is in to the front or, if it is already
>	    at the front, pushes it to the back, and
>	    <keycap>F15</keycap> pops up the main Workplace
>	    menu even if the cursor is not on the
>	    desktop, which is useful when no part of
>	    the desktop is visible.</para>
>
>	  <para>The following entries in
>	    <filename>~/.fvwmrc</filename> implement the
>	    aforementioned setup:</para>
>
>	  <programlisting>Key F13        FTIWS    A        Iconify
>Key F14        FTIWS    A        RaiseLower
>Key F15        A        A        Menu Workplace Nop</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="x-3d-acceleration">
>	  <para>How can I get 3D hardware acceleration for
>	    &opengl;?</para>
>	</question>
>
>	<answer>
>	  <para>The availability of 3D acceleration depends on the
>	    version of &xorg; and the type of video
>	    chip.  For an nVidia chip, use
>	    the binary drivers provided for &os; by installing one of
>	    the following ports:</para>
>
>	  <para>The latest versions of nVidia cards are supported
>	    by the <package>x11/nvidia-driver</package>
>	    port.</para>
>
>	  <para>Older drivers are available as
>	    <package>x11/nvidia-driver-<replaceable>###</replaceable></package></para>
>
>	  <para>nVidia provides detailed information on which
>	    card is supported by which driver on their web site: <uri
>	      xlink:href="http://www.nvidia.com/object/IO_32667.html">http://www.nvidia.com/object/IO_32667.html</uri>.</para>
>
>	  <para>For Matrox&nbsp;G200/G400, check the
>	    <package>x11-servers/mga_hal</package>
>	    port.</para>
>
>	  <para>For ATI&nbsp;Rage&nbsp;128 and Radeon see
>	    &man.ati.4x;, &man.r128.4x; and &man.radeon.4x;.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="networking">
>    <title>Networking</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="diskless-booting">
>	  <para>Where can I get information on <quote>diskless
>	      booting</quote>?</para>
>	</question>
>
>	<answer>
>	  <para><quote>Diskless booting</quote> means that the &os;
>	    box is booted over a network, and reads the necessary
>	    files from a server instead of its hard disk.  For full
>	    details, see <link
>	      xlink:href="&url.books.handbook;/network-diskless.html">the
>	      Handbook entry on diskless booting</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="router">
>	  <para>Can a &os; box be used as a dedicated network
>	    router?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  Refer to the Handbook entry on <link
>	      xlink:href="&url.books.handbook;/advanced-networking.html">advanced
>	      networking</link>, specifically the section on <link
>	      xlink:href="&url.books.handbook;/network-routing.html">routing
>	      and gateways</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="win95-connection">
>	  <para>Can I connect my &windows; box to the Internet via
>	    &os;?</para>
>	</question>
>
>	<answer>
>	  <para>Typically, people who ask this question have two PCs
>	    at home, one with &os; and one with some version of
>	    &windows; the idea is to use the &os; box to connect to
>	    the Internet and then be able to access the Internet from
>	    the &windows; box through the &os; box.  This is really
>	    just a special case of the previous question and works
>	    perfectly well.</para>
>
>	  <para>Dialup users must use <option>-nat</option>
>	    and set <literal>gateway_enable</literal> to
>	    <emphasis>YES</emphasis> in
>	    <filename>/etc/rc.conf</filename>.  For more information,
>	    refer to &man.ppp.8; or the <link
>	      xlink:href="&url.books.handbook;/userppp.html">Handbook
>	      entry on user PPP</link>.</para>
>
>	  <para>If the connection to the Internet is over Ethernet,
>	    use &man.natd.8;.  A tutorial can be found in the <link
>	      xlink:href="&url.books.handbook;/firewalls-ipfw.html#network-natd">natd</link>
>	    section of the Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="slip-ppp-support">
>	  <para>Does &os; support PPP?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  &man.ppp.8; provides support for both incoming
>	    and outgoing connections.</para>
>
>	  <para>For more information on how to use this, refer to
>	    the <link
>	      xlink:href="&url.books.handbook;/ppp-and-slip.html">Handbook
>	      chapter on PPP</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="natd">
>	  <para>Does &os; support NAT or Masquerading?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  For instructions on how to use NAT over a PPP
>	    connection, see the <link
>	      xlink:href="&url.books.handbook;/userppp.html">Handbook
>	      entry on PPP</link>.  To use NAT over
>	    some other sort of network connection, look at the
>	    <link
>	      xlink:href="&url.books.handbook;/firewalls-ipfw.html#network-natd">natd</link>
>	    section of the Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ethernet-aliases">
>	  <para>How can I set up Ethernet aliases?</para>
>	</question>
>
>	<answer>
>	  <para>If the alias is on the same subnet as an address
>	    already configured on the interface, add
>	    <literal>netmask 0xffffffff</literal> to this
>	    command:</para>
>
>	  <screen>&prompt.root; <userinput>ifconfig <replaceable>ed0</replaceable> alias <replaceable>192.0.2.2 </replaceable>netmask 0xffffffff</userinput></screen>
>
>	  <para>Otherwise, specify the network address and
>	    netmask as usual:</para>
>
>	  <screen>&prompt.root; <userinput>ifconfig <replaceable>ed0</replaceable> alias <replaceable>172.16.141.5</replaceable> netmask 0xffffff00</userinput></screen>
>
>	  <para>More information can be found in the &os; <link
>	      xlink:href="&url.books.handbook;/configtuning-virtual-hosts.html">Handbook</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="nfs-linux">
>	  <para>Why can I not NFS-mount from a &linux; box?</para>
>	</question>
>
>	<answer>
>	  <para>Some versions of the &linux; NFS code only accept
>	    mount requests from a privileged port; try to issue the
>	    following command:</para>
>
>	  <screen>&prompt.root; <userinput>mount -o -P linuxbox:/blah /mnt</userinput></screen>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="exports-errors">
>	  <para>Why does <command>mountd</command> keep telling me it
>	    <errorname>can't change attributes</errorname> and that I
>	    have a <errorname>bad exports list</errorname> on my &os;
>	    NFS server?</para>
>	</question>
>
>	<answer>
>	  <para>The most frequent problem is not understanding the
>	    correct format of <filename>/etc/exports</filename>.
>	    Review &man.exports.5; and the <link
>	      xlink:href="&url.books.handbook;/network-nfs.html">NFS</link>
>	    entry in the Handbook, especially the section on <link
>	      xlink:href="&url.books.handbook;/network-nfs.html#configuring-nfs">configuring
>	      NFS</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ip-multicast">
>	  <para>How do I enable IP multicast support?</para>
>	</question>
>
>	<answer>
>	  <para>Install the <package>net/mrouted</package> package
>	    or port and add
>	    <literal>mrouted_enable="YES"</literal> to
>	    <filename>/etc/rc.conf</filename> start this service at
>	    boot time.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="fqdn-hosts">
>	  <para>Why do I have to use the FQDN for hosts on my
>	    site?</para>
>	</question>
>
>	<answer>
>	  <para>See the answer in the &os; <link
>	      xlink:href="&url.books.handbook;/mail-trouble.html">Handbook</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="network-permission-denied">
>	  <para>Why do I get an error, <errorname>Permission
>	      denied</errorname>, for all networking
>	    operations?</para>
>	</question>
>
>	<answer>
>	  <para>If the kernel is compiled with the
>	    <literal>IPFIREWALL</literal> option, be aware
>	    that the default policy is to deny all packets that are
>	    not explicitly allowed.</para>
>
>	  <para>If the firewall is unintentionally misconfigured,
>	    restore network operability by
>	    typing the following as <systemitem
>	      class="username">root</systemitem>:</para>
>
>	  <screen>&prompt.root; <userinput>ipfw add 65534 allow all from any to any</userinput></screen>
>
>	  <para>Consider setting
>	    <literal>firewall_type="open"</literal> in
>	    <filename>/etc/rc.conf</filename>.</para>
>
>	  <para>For further information on configuring this
>	    firewall, see the <link
>	      xlink:href="&url.books.handbook;/firewalls-ipfw.html">Handbook
>	      chapter</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ipfw-fwd">
>	  <para>Why is my <command>ipfw</command> <quote>fwd</quote>
>	    rule to redirect a service to another machine not
>	    working?</para>
>	</question>
>
>	<answer>
>	  <para>Possibly because network address translation (NAT) is
>	    needed instead of just forwarding packets.  A
>	    <quote>fwd</quote> rule only forwards packets, it does not
>	    actually change the data inside the packet.  Consider this
>	    rule:</para>
>
>	  <screen>01000 fwd <replaceable>10.0.0.1</replaceable> from any to <replaceable>foo 21</replaceable></screen>
>
>	  <para>When a packet with a destination address of
>	    <replaceable>foo</replaceable> arrives at the machine with
>	    this rule, the packet is forwarded to
>	    <replaceable>10.0.0.1</replaceable>, but it still has the
>	    destination address of <replaceable>foo</replaceable>.
>	    The destination address of the packet is
>	    not changed to
>	    <replaceable>10.0.0.1</replaceable>.  Most machines would
>	    probably drop a packet that they receive with a
>	    destination address that is not their own.  Therefore,
>	    using a <quote>fwd</quote> rule does not often work the
>	    way the user expects.  This behavior is a feature and not
>	    a bug.</para>
>
>	  <para>See the <link
>	      linkend="service-redirect"><acronym>FAQ</acronym> about
>	      redirecting services</link>, the &man.natd.8; manual, or
>	    one of the several port redirecting utilities in the <link
>	      xlink:href="&url.base;/ports/index.html">Ports
>	      Collection</link> for a correct way to do this.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="service-redirect">
>	  <para>How can I redirect service requests from one machine
>	    to another?</para>
>	</question>
>
>	<answer>
>	  <para>FTP and other service requests can be redirected with
>	    the <package>sysutils/socket</package> package or port.
>	    Replace the entry for the service in
>	    <filename>/etc/inetd.conf</filename> to call
>	    <command>socket</command>, as seen in this example for
>	    <application>ftpd</application>:</para>
>
>	  <programlisting>ftp stream tcp nowait nobody /usr/local/bin/socket socket <replaceable>ftp.example.com</replaceable> <replaceable>ftp</replaceable></programlisting>
>
>	  <para>where <replaceable>ftp.example.com</replaceable> and
>	    <replaceable>ftp</replaceable> are the host and port to
>	    redirect to, respectively.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="bandwidth-mgr-tool">
>	  <para>Where can I get a bandwidth management tool?</para>
>	</question>
>
>	<answer>
>	  <para>There are three bandwidth management tools available
>	    for &os;.  &man.dummynet.4; is integrated into &os; as
>	    part of &man.ipfw.4;.  <link
>	      xlink:href="http://www.sonycsl.co.jp/person/kjc/programs.html">ALTQ</link>
>	    has been integrated into &os; as part of &man.pf.4;.
>	    Bandwidth Manager from <link
>	      xlink:href="http://www.etinc.com/">Emerging
>	      Technologies</link> is a commercial product.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="bpf-not-configured">
>	  <para>Why do I get <errorname>/dev/bpf0: device not
>	      configured</errorname>?</para>
>	</question>
>
>	<answer>
>	  <para>The running application requires the Berkeley
>	    Packet Filter (&man.bpf.4;), but it was removed from a
>	    custom kernel.  Add this to the kernel config file and
>	    build a new kernel:</para>
>
>	  <programlisting>device bpf        # Berkeley Packet Filter</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="mount-smb-share">
>	  <para>How do I mount a disk from a &windows; machine that is
>	    on my network, like smbmount in &linux;?</para>
>	</question>
>
>	<answer>
>	  <para>Use the <application>SMBFS</application> toolset.  It
>	    includes a set of kernel modifications and a set of
>	    userland programs.  The programs and information are
>	    available as &man.mount.smbfs.8; in the base
>	    system.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="icmp-response-bw-limit">
>	  <para>What are these messages about: <errorname>Limiting
>	      icmp/open port/closed port response</errorname> in my
>	    log files?</para>
>	</question>
>
>	<answer>
>	  <para>This kernel message indicates that some activity is
>	    provoking it to send a large amount of ICMP or TCP reset
>	    (RST) responses.  ICMP responses are
>	    often generated as a result of attempted connections to
>	    unused UDP ports.  TCP resets are generated as a result of
>	    attempted connections to unopened TCP ports.  Among
>	    others, these are the kinds of activities which may cause
>	    these messages:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>Brute-force denial of service (DoS) attacks (as
>		opposed to single-packet attacks which exploit a
>		specific vulnerability).</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Port scans which attempt to connect to a large
>		number of ports (as opposed to only trying a few
>		well-known ports).</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>The first number in the message indicates how many
>	    packets the kernel would have sent if the limit was not in
>	    place, and the second indicates the limit.  This limit
>	    is controlled using
>	    <varname>net.inet.icmp.icmplim</varname>.  This example
>	    sets the limit to <literal>300</literal>
>	    packets per second:</para>
>
>	  <screen>&prompt.root; <userinput>sysctl net.inet.icmp.icmplim=300</userinput></screen>
>
>	  <para>To disable these messages
>	    without disabling response
>	    limiting, use
>	    <varname>net.inet.icmp.icmplim_output</varname>
>	    to disable the output:</para>
>
>	  <screen>&prompt.root; <userinput>sysctl net.inet.icmp.icmplim_output=0</userinput></screen>
>
>	  <para>Finally, to disable response limiting completely,
>	    set <varname>net.inet.icmp.icmplim</varname> to
>	    <literal>0</literal>.  Disabling response limiting is
>	    discouraged for the reasons listed above.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="unknown-hw-addr-format">
>	  <para>What are these <errorname>arp: unknown hardware
>	      address format</errorname> error messages?</para>
>	</question>
>
>	<answer>
>	  <para>This means that some device on the local Ethernet is
>	    using a MAC address in a format that &os; does not
>	    recognize.  This is probably caused by someone
>	    experimenting with an Ethernet card somewhere else on the
>	    network.  This is most commonly seen on cable modem
>	    networks.  It is harmless, and should not affect the
>	    performance of the &os; system.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="arp-wrong-iface">
>	  <para>Why do I keep seeing messages like:
>	    <errorname>192.168.0.10 is on
>	      fxp1 but got reply from 00:15:17:67:cf:82 on
>	      rl0</errorname>, and how do I disable it?</para>
>	</question>
>
>	<answer>
>	  <para>Because a packet is coming from outside the network
>	    unexpectedly.  To disable them, set
>	    <varname>net.link.ether.inet.log_arp_wrong_iface</varname>
>	    to <literal>0</literal>.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="security">
>    <title>Security</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="sandbox">
>	  <para>What is a sandbox?</para>
>	</question>
>	<answer>
>	  <para><quote>Sandbox</quote> is a security term.  It can
>	    mean two things:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>A process which is placed inside a set of virtual
>		walls that are designed to prevent someone who breaks
>		into the process from being able to break into the
>		wider system.</para>
>
>	      <para>The process is be able to run inside the walls.
>		Since nothing the process does in regards to executing
>		code is supposed to be able to breech the walls, a
>		detailed audit of its code is not needed in order to
>		be able to say certain things about its
>		security.</para>
>
>	      <para>The walls might be a user ID, for example.
>		This is the definition used in the &man.security.7;
>		and &man.named.8; man pages.</para>
>
>	      <para>Take the <literal>ntalk</literal> service, for
>		example (see &man.inetd.8;).  This service used to run
>		as user&nbsp;ID <systemitem
>		  class="username">root</systemitem>.  Now it runs as
>		user&nbsp;ID <systemitem
>		  class="username">tty</systemitem>.  The <systemitem
>		  class="username">tty</systemitem> user is a sandbox
>		designed to make it more difficult for someone who has
>		successfully hacked into the system via
>		<literal>ntalk</literal> from being able to hack
>		beyond that user&nbsp;ID.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>A process which is placed inside a simulation of
>		the machine.  It means that someone who is able to
>		break into the process may believe that he can break
>		into the wider machine but is, in fact, only breaking
>		into a simulation of that machine and not modifying
>		any real data.</para>
>
>	      <para>The most common way to accomplish this is to build
>		a simulated environment in a subdirectory and then run
>		the processes in that directory chrooted so that
>		<filename>/</filename> for that process is this
>		directory, not the real <filename>/</filename> of the
>		system).</para>
>
>	      <para>Another common use is to mount an underlying file
>		system read-only and then create a file system layer
>		on top of it that gives a process a seemingly
>		writeable view into that file system.  The process may
>		believe it is able to write to those files, but only
>		the process sees the effects &mdash; other processes
>		in the system do not, necessarily.</para>
>
>	      <para>An attempt is made to make this sort of sandbox so
>		transparent that the user (or hacker) does not realize
>		that he is sitting in it.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>&unix; implements two core sandboxes.  One is at the
>	    process level, and one is at the userid level.</para>
>
>	  <para>Every &unix; process is completely firewalled off from
>	    every other &unix; process.  One process cannot modify the
>	    address space of another.</para>
>
>	  <para>A &unix; process is owned by a particular userid.  If
>	    the user&nbsp;ID is not the <systemitem
>	      class="username">root</systemitem> user, it serves to
>	    firewall the process off from processes owned by other
>	    users.  The user&nbsp;ID is also used to firewall off
>	    on-disk data.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="securelevel">
>	  <para>What is securelevel?</para>
>	</question>
>
>	<answer>
>	  <para><literal>securelevel</literal> is a security
>	    mechanism implemented in the kernel.  When the securelevel
>	    is positive, the kernel restricts certain tasks; not even
>	    the superuser (<systemitem
>	      class="username">root</systemitem>) is allowed to do
>	    them.  The securelevel mechanism limits the ability
>	    to:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>Unset certain file flags, such as
>		<literal>schg</literal> (the system immutable
>		flag).</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Write to kernel memory via
>		<filename>/dev/mem</filename> and
>		<filename>/dev/kmem</filename>.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Load kernel modules.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Alter firewall rules.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>To check the status of the securelevel on a running
>	    system:</para>
>
>	  <screen>&prompt.root; <userinput>sysctl -n kern.securelevel</userinput></screen>
>
>	  <para>The output contains the current value of the
>	    securelevel.  If it is greater than 0, at
>	    least some of the securelevel's protections are
>	    enabled.</para>
>
>	  <para>The securelevel of a running system cannot be lowered
>	    as this would defeat its purpose.  If a task requires that
>	    the securelevel be non-positive, change the
>	    <varname>kern_securelevel</varname> and
>	    <varname>kern_securelevel_enable</varname> variables in
>	    <filename>/etc/rc.conf</filename> and reboot.</para>
>
>	  <para>For more information on securelevel and the specific
>	    things all the levels do, consult &man.init.8;.</para>
>
>	  <warning>
>	    <para>Securelevel is not a silver bullet; it has many
>	      known deficiencies.  More often than not, it provides a
>	      false sense of security.</para>
>
>	    <para>One of its biggest problems is that in order for it
>	      to be at all effective, all files used in the boot
>	      process up until the securelevel is set must be
>	      protected.  If an attacker can get the system to execute
>	      their code prior to the securelevel being set (which
>	      happens quite late in the boot process since some things
>	      the system must do at start-up cannot be done at an
>	      elevated securelevel), its protections are invalidated.
>	      While this task of protecting all files used in the boot
>	      process is not technically impossible, if it is
>	      achieved, system maintenance will become a nightmare
>	      since one would have to take the system down, at least
>	      to single-user mode, to modify a configuration
>	      file.</para>
>
>	    <para>This point and others are often discussed on the
>	      mailing lists, particularly the &a.security;.
>	      Search the archives <link
>		xlink:href="&url.base;/search/index.html">here</link>
>	      for an extensive discussion.  A more fine-grained
>	      mechanism is preferred.</para>
>	  </warning>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="extra-named-port">
>	  <para>BIND (<command>named</command>) is listening on some
>	    high-numbered ports.  What is going on?</para>
>	</question>
>
>	<answer>
>	  <para>BIND uses a random high-numbered port for outgoing
>	    queries.  Recent versions of it choose a new, random UDP
>	    port for each query.  This may cause problems for some
>	    network configurations, especially if a firewall blocks
>	    incoming UDP packets on particular ports.  To
>	    get past that firewall, try the
>	    <literal>avoid-v4-udp-ports</literal> and
>	    <literal>avoid-v6-udp-ports</literal> options to avoid
>	    selecting random port numbers within a blocked
>	    range.</para>
>
>	  <warning>
>	    <para>If a port number (like 53) is specified via the
>	      <literal>query-source</literal> or
>	      <literal>query-source-v6</literal> options in
>	      <filename>/etc/namedb/named.conf</filename>, randomized
>	      port selection will not be used.  It is strongly
>	      recommended that these options not be used to specify
>	      fixed port numbers.</para>
>	  </warning>
>
>	  <para>Congratulations, by the way.  It is good practice to
>	    read &man.sockstat.1; output and notice odd
>	    things!</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="sendmail-port-587">
>	  <para>The <application>Sendmail</application> daemon is
>	    listening on port 587 as well as the standard port 25!
>	    What is going on?</para>
>	</question>
>
>	<answer>
>	  <para>Recent versions of <application>Sendmail</application>
>	    support a mail submission feature that runs over port 587.
>	    This is not yet widely supported, but is growing in
>	    popularity.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="toor-account">
>	  <para>What is this UID 0 <systemitem
>	      class="username">toor</systemitem> account?  Have I been
>	    compromised?</para>
>	</question>
>
>	<answer>
>	  <para>Do not worry.  <systemitem
>	      class="username">toor</systemitem> is an
>	    <quote>alternative</quote> superuser account, where toor
>	    is root spelled backwards.  It is intended to be used with
>	    a non-standard shell so the default shell for <systemitem
>	      class="username">root</systemitem> does not need to
>	    change.  This is important as shells which are not part of
>	    the base distribution, but are instead installed from
>	    ports or packages, are installed in
>	    <filename>/usr/local/bin</filename> which, by default,
>	    resides on a different file system.  If <systemitem
>	      class="username">root</systemitem>'s shell is located in
>	    <filename>/usr/local/bin</filename> and the
>	    file system
>	    containing <filename>/usr/local/bin</filename>) is not
>	    mounted, <systemitem
>	      class="username">root</systemitem> will not be able to
>	    log in to fix a problem and will have to reboot into
>	    single-user mode in order to enter the path to a
>	    shell.</para>
>
>	  <para>Some people use <systemitem
>	      class="username">toor</systemitem> for day-to-day
>	    <systemitem class="username">root</systemitem> tasks with
>	    a non-standard shell, leaving <systemitem
>	      class="username">root</systemitem>, with a standard
>	    shell, for single-user mode or emergencies.  By default, a
>	    user cannot log in using <systemitem
>	      class="username">toor</systemitem> as it does not have a
>	    password, so log in as <systemitem
>	      class="username">root</systemitem> and set a password
>	    for <systemitem class="username">toor</systemitem> before
>	    using it to login.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="ppp">
>    <title>PPP</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="userppp">
>	  <para>I cannot make &man.ppp.8; work.  What am I doing
>	    wrong?</para>
>	</question>
>
>	<answer>
>	  <para>First, read &man.ppp.8; and
>	    the <link
>	      xlink:href="&url.books.handbook;/ppp-and-slip.html#userppp">PPP
>	      section of the Handbook</link>.  To assist in
>	    troubleshooting, enable logging with the
>	    following command:</para>
>
>	  <programlisting>set log Phase Chat Connect Carrier lcp ipcp ccp command</programlisting>
>
>	  <para>This command may be typed at the &man.ppp.8; command
>	    prompt or it may be entered at the start of the
>	    <literal>default</literal> section
>	    in <filename>/etc/ppp/ppp.conf</filename>.  Make sure that
>	    <filename>/etc/syslog.conf</filename> contains the lines
>	    below and the file <filename>/var/log/ppp.log</filename>
>	    exists:</para>
>
>	  <programlisting>!ppp
>*.*        /var/log/ppp.log</programlisting>
>
>	  <para>A lot about what is going can be learned from the log
>	    file.  Do not worry if it does not all make sense as
>	    it may make sense to someone else.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-hangs">
>	  <para>Why does &man.ppp.8; hang when I run it?</para>
>	</question>
>
>	<answer>
>	  <para>This is usually because the hostname will not
>	    resolve.  The best way to fix this is to make sure that
>	    <filename>/etc/hosts</filename> is read first by the
>	    by ensuring that the <literal>hosts</literal> line is
>	    listed first in <filename>/etc/host.conf</filename>.
>	    Then, put an entry in <filename>/etc/hosts</filename> for
>	    the local machine.  If there is no local network, change
>	    the <systemitem>localhost</systemitem> line:</para>
>
>	  <programlisting>127.0.0.1        foo.example.com foo localhost</programlisting>
>
>	  <para>Otherwise, add another entry for the host.
>	    Consult the relevant manual pages for more details.</para>
>
>	  <para>When finished, verify that this command is successful:
>	    <command>ping -c1 `hostname`</command>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-nodial-auto">
>	  <para>Why will &man.ppp.8; not dial in
>	    <literal>-auto</literal> mode?</para>
>	</question>
>
>	<answer>
>	  <para>First, check that a default route exists.  This
>	    command should display two entries:</para>
>
>	  <programlisting>Destination        Gateway            Flags     Refs     Use     Netif Expire
>default            10.0.0.2           UGSc        0        0      tun0
>10.0.0.2           10.0.0.1           UH          0        0      tun0</programlisting>
>
>	  <para>If
>	    a default route is not listed, make sure that the
>	    <literal>HISADDR</literal> line has been added to
>	    <filename>/etc/ppp/ppp.conf</filename>.</para>
>
>	  <para>Another reason for the default route line being
>	    missing is that a default
>	    route has been added to <filename>/etc/rc.conf</filename>
>	    and this line is missing
>	    from <filename>/etc/ppp/ppp.conf</filename>:</para>
>
>	  <programlisting>delete ALL</programlisting>
>
>	  <para>If this is the case, go back to the <link
>	      xlink:href="&url.books.handbook;/userppp.html#userppp-final">Final
>	      System Configuration</link> section of the
>	    Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="no-route-to-host">
>	  <para>What does <errorname>No route to host</errorname>
>	    mean?</para>
>	</question>
>
>	<answer>
>	  <para>This error is usually because the following section
>	    is missing in
>	    <filename>/etc/ppp/ppp.linkup</filename>:</para>
>
>	  <programlisting>MYADDR:
>  delete ALL
>  add 0 0 HISADDR</programlisting>
>
>	  <para>This is only necessary for a dynamic IP address or
>	    when the address of the default gateway is unknown.  When
>	    using interactive mode, the following can be typed in
>	    after entering packet mode.  Packet mode
>	    is indicated by the capitalized <acronym>PPP</acronym> in
>	    the prompt:</para>
>
>	  <programlisting>delete ALL
>add 0 0 HISADDR</programlisting>
>
>	  <para>Refer to the <link
>	      xlink:href="&url.books.handbook;/userppp.html#userppp-dynamicip">PPP
>	      and Dynamic IP addresses</link> section of the Handbook
>	    for further details.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="connection-threeminutedrop">
>	  <para>Why does my connection drop after about 3
>	    minutes?</para>
>	</question>
>
>	<answer>
>	  <para>The default PPP timeout is 3 minutes.  This can be
>	    adjusted with the following line:</para>
>
>	  <programlisting>set timeout <replaceable>NNN</replaceable></programlisting>
>
>	  <para>where <replaceable>NNN</replaceable> is the number of
>	    seconds of inactivity before the connection is closed.  If
>	    <replaceable>NNN</replaceable> is zero, the connection is
>	    never closed due to a timeout.  It is possible to put this
>	    command in <filename>ppp.conf</filename>, or to type it at
>	    the prompt in interactive mode.  It is also possible to
>	    adjust it on the fly while the line is active by
>	    connecting to <application>ppp</application>'s server
>	    socket using &man.telnet.1; or &man.pppctl.8;.  Refer to
>	    the &man.ppp.8; man page for further details.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-drop-heavy-load">
>	  <para>Why does my connection drop under heavy load?</para>
>	</question>
>
>	<answer>
>	  <para>If Link Quality Reporting (<acronym>LQR</acronym>) is
>	    configured, it is possible that too many
>	    <acronym>LQR</acronym> packets are lost between the &os;
>	    system and the peer.  &man.ppp.8; deduces that the line
>	    must therefore be bad, and disconnects.
>	    <acronym>LQR</acronym> is disabled by default and can be
>	    enabled with the following line:</para>
>
>	  <programlisting>enable lqr</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-drop-random">
>	  <para>Why does my connection drop after a random amount of
>	    time?</para>
>	</question>
>
>	<answer>
>	  <para>Sometimes, on a noisy phone line or even on a line
>	    with call waiting enabled, the modem may hang up because
>	    it incorrectly thinks that it lost carrier.</para>
>
>	  <para>There is a setting on most modems for determining how
>	    tolerant it should be to temporary losses of carrier.
>	    Refer to the modem manual for details.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-hangs-random">
>	  <para>Why does my connection hang after a random amount of
>	    time?</para>
>	</question>
>
>	<answer>
>	  <para>Many people experience hung connections with no
>	    apparent explanation.  The first thing to establish is
>	    which side of the link is hung.</para>
>
>	  <para>When using an external modem, try
>	    using &man.ping.8; to see if the <acronym>TD</acronym>
>	    light is flashing when data is transmitted.  If it flashes
>	    but the <acronym>RD</acronym> light does not, the
>	    problem is with the remote end.  If <acronym>TD</acronym>
>	    does not flash, the problem is local.  With an internal
>	    modem, use the <literal>set
>	      server</literal> command in
>	    <filename>ppp.conf</filename>.  When the hang occurs,
>	    connect to &man.ppp.8; using &man.pppctl.8;.  If the
>	    network connection suddenly revives due to the activity on
>	    the diagnostic socket, or if it will not
>	    connect but the <literal>set socket</literal>
>	    command succeeded at startup time, the problem is local.
>	    If it can connect but things are still hung, enable local
>	    logging with <literal>set log local async</literal>
>	    and use &man.ping.8; from another window or terminal to
>	    make use of the link.  The async logging will show the
>	    data being transmitted and received on the link.  If data
>	    is going out and not coming back, the problem is
>	    remote.</para>
>
>	  <para>Having established whether the problem is local or
>	    remote, there are now two possibilities:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>If the problem is remote, read on entry <xref
>		  linkend="ppp-remote-not-responding"/>.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>If the problem is local, read on entry <xref
>		  linkend="ppp-hung"/>.</para>
>	    </listitem>
>	  </itemizedlist>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-remote-not-responding">
>	  <para>The remote end is not responding.  What can I
>	    do?</para>
>	</question>
>
>	<answer>
>	  <para>There is very little that can be done about this.
>	    Many ISPs will refuse to help users not running a
>	    &microsoft; OS.  Add <literal>enable lqr</literal> to
>	    <filename>/etc/ppp/ppp.conf</filename>, allowing
>	    &man.ppp.8; to detect the remote failure and hang up.
>	    This detection is relatively slow and therefore not that
>	    useful.</para>
>
>	  <para>First, try disabling all local compression by adding
>	    the following to the configuration:</para>
>
>	  <programlisting>disable pred1 deflate deflate24 protocomp acfcomp shortseq vj
>deny pred1 deflate deflate24 protocomp acfcomp shortseq vj</programlisting>
>
>	  <para>Then reconnect to ensure that this makes no
>	    difference.  If things improve or if the problem is solved
>	    completely, determine which setting makes the difference
>	    through trial and error.  This is good information for
>	    the ISP, although it may make
>	    it apparent that it is not a &microsoft; system.</para>
>
>	  <para>Before contacting the ISP, enable async logging
>	    locally and wait until the connection hangs again.  This
>	    may use up quite a bit of disk space.  The last data read
>	    from the port may be of interest.  It is usually ASCII
>	    data, and may even describe the problem (<errorname>Memory
>	      fault</errorname>, <errorname>Core
>	      dumped</errorname>).</para>
>
>	  <para>If the ISP is helpful, they should be able to enable
>	    logging on their end, then when the next link drop occurs,
>	    they may be able to tell why their side is having a
>	    problem.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-hung">
>	  <para>&man.ppp.8; has hung.  What can I do?</para>
>	</question>
>
>	<answer>
>	  <para>In this case, rebuild &man.ppp.8; with
>	    debugging information, and then use &man.gdb.1; to grab a
>	    stack trace from the <application>ppp</application>
>	    process that is stuck.  To rebuild the
>	    <application>ppp</application> utility with debugging
>	    information, type:</para>
>
>	  <screen>&prompt.root; <userinput>cd /usr/src/usr.sbin/ppp</userinput>
>&prompt.root; <userinput>env DEBUG_FLAGS='-g' make clean</userinput>
>&prompt.root; <userinput>env DEBUG_FLAGS='-g' make install</userinput></screen>
>
>	  <para>Then, restart <application>ppp</application>
>	    and wait until it hangs again.  When the debug build of
>	    <application>ppp</application> hangs, start
>	    <application>gdb</application> on the stuck process by
>	    typing:</para>
>
>	  <screen>&prompt.root; <userinput>gdb ppp `pgrep ppp`</userinput></screen>
>
>	  <para>At the <application>gdb</application> prompt,
>	    use the <command>bt</command> or <command>where</command>
>	    commands to get a stack trace.  Save the output of the
>	    <application>gdb</application> session, and
>	    <quote>detach</quote> from the running process by typing
>	    <command>quit</command>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-same-magic">
>	  <para>I keep seeing errors about magic being the same.  What
>	    does it mean?</para>
>	</question>
>
>	<answer>
>	  <para>Occasionally, just after connecting, there may be
>	    messages in the log that say <errorname>Magic is
>	      same</errorname>.  Sometimes, these messages are
>	    harmless, and sometimes one side or the other exits.  Most
>	    PPP implementations cannot survive this problem, and even
>	    if the link seems to come up, there will be repeated
>	    configure requests and configure acknowledgments in the
>	    log file until &man.ppp.8; eventually gives up and closes
>	    the connection.</para>
>
>	  <para>This normally happens on server machines with slow
>	    disks that are spawning a &man.getty.8; on the port, and
>	    executing &man.ppp.8; from a login script or program after
>	    login.  There were reports of it happening consistently
>	    when using slirp.  The reason is that in the time taken
>	    between &man.getty.8; exiting and &man.ppp.8; starting,
>	    the client-side &man.ppp.8; starts sending Line Control
>	    Protocol (LCP) packets.  Because ECHO is still switched on
>	    for the port on the server, the client &man.ppp.8; sees
>	    these packets <quote>reflect</quote> back.</para>
>
>	  <para>One part of the LCP negotiation is to establish a
>	    magic number for each side of the link so that
>	    <quote>reflections</quote> can be detected.  The protocol
>	    says that when the peer tries to negotiate the same magic
>	    number, a NAK should be sent and a new magic number should
>	    be chosen.  During the period that the server port has
>	    ECHO turned on, the client &man.ppp.8; sends LCP packets,
>	    sees the same magic in the reflected packet and NAKs it.
>	    It also sees the NAK reflect (which also means &man.ppp.8;
>	    must change its magic).  This produces a potentially
>	    enormous number of magic number changes, all of which are
>	    happily piling into the server's tty buffer.  As soon as
>	    &man.ppp.8; starts on the server, it is flooded with magic
>	    number changes and almost immediately decides it has tried
>	    enough to negotiate LCP and gives up.  Meanwhile, the
>	    client, who no longer sees the reflections, becomes happy
>	    just in time to see a hangup from the server.</para>
>
>	  <para>This can be avoided by allowing the peer to start
>	    negotiating with the following line in
>	    <filename>ppp.conf</filename>:</para>
>
>	  <programlisting>set openmode passive</programlisting>
>
>	  <para>This tells &man.ppp.8; to wait for the server to
>	    initiate LCP negotiations.  Some servers however may never
>	    initiate negotiations.  In this case, try
>	    something like:</para>
>
>	  <programlisting>set openmode active 3</programlisting>
>
>	  <para>This tells &man.ppp.8; to be passive for 3 seconds,
>	    and then to start sending LCP requests.  If the peer
>	    starts sending requests during this period, &man.ppp.8;
>	    will immediately respond rather than waiting for the full
>	    3 second period.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-lcp-constant">
>	  <para>LCP negotiations continue until the connection is
>	    closed.  What is wrong?</para>
>	</question>
>
>	<answer>
>	  <para>There is currently an implementation mis-feature in
>	    &man.ppp.8; where it does not associate LCP, CCP &amp;
>	    IPCP responses with their original requests.  As a result,
>	    if one PPP implementation is more than 6 seconds slower
>	    than the other side, the other side will send two
>	    additional LCP configuration requests.  This is
>	    fatal.</para>
>
>	  <para>Consider two implementations,
>	    <systemitem>A</systemitem> and <systemitem>B</systemitem>.
>	    <systemitem>A</systemitem> starts sending LCP requests
>	    immediately after connecting and
>	    <systemitem>B</systemitem> takes 7 seconds to start.  When
>	    <systemitem>B</systemitem> starts,
>	    <systemitem>A</systemitem> has sent 3 LCP REQs.  We are
>	    assuming the line has ECHO switched off, otherwise we
>	    would see magic number problems as described in the
>	    previous section.  <systemitem>B</systemitem> sends a REQ,
>	    then an ACK to the first of <systemitem>A</systemitem>'s
>	    REQs.  This results in <systemitem>A</systemitem> entering
>	    the <acronym>OPENED</acronym> state and sending and ACK
>	    (the first) back to <systemitem>B</systemitem>.  In the
>	    meantime, <systemitem>B</systemitem> sends back two more
>	    ACKs in response to the two additional REQs sent by
>	    <systemitem>A</systemitem> before
>	    <systemitem>B</systemitem> started up.
>	    <systemitem>B</systemitem> then receives the first ACK
>	    from <systemitem>A</systemitem> and enters the
>	    <acronym>OPENED</acronym> state.
>	    <systemitem>A</systemitem> receives the second ACK from
>	    <systemitem>B</systemitem> and goes back to the
>	    <acronym>REQ-SENT</acronym> state, sending another (forth)
>	    REQ as per the RFC.  It then receives the third ACK and
>	    enters the <acronym>OPENED</acronym> state.  In the
>	    meantime, <systemitem>B</systemitem> receives the forth
>	    REQ from <systemitem>A</systemitem>, resulting in it
>	    reverting to the <acronym>ACK-SENT</acronym> state and
>	    sending another (second) REQ and (forth) ACK as per the
>	    RFC.  <systemitem>A</systemitem> gets the REQ, goes into
>	    <acronym>REQ-SENT</acronym> and sends another REQ.  It
>	    immediately receives the following ACK and enters
>	    <acronym>OPENED</acronym>.</para>
>
>	  <para>This goes on until one side figures out that they are
>	    getting nowhere and gives up.</para>
>
>	  <para>The best way to avoid this is to configure one side to
>	    be <literal>passive</literal> &mdash; that is, make one
>	    side wait for the other to start negotiating.  This can be
>	    done with the following command:</para>
>
>	  <programlisting>set openmode passive</programlisting>
>
>	  <para>Care should be taken with this option.  This command
>	    can also be used to limit the amount of time that
>	    &man.ppp.8; waits for the peer to begin
>	    negotiations:</para>
>
>	  <programlisting>set stopped <replaceable>N</replaceable></programlisting>
>
>	  <para>Alternatively, the following command (where
>	    <replaceable>N</replaceable> is the number of seconds to
>	    wait before starting negotiations) can be used:</para>
>
>	  <programlisting>set openmode active <replaceable>N</replaceable></programlisting>
>
>	  <para>Check the manual page for details.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-shell-test-lockup">
>	  <para>Why does &man.ppp.8; lock up when I shell out to test
>	    it?</para>
>	</question>
>
>	<answer>
>	  <para>When using <command>shell</command> or
>	    <command>!</command>, &man.ppp.8; executes a shell
>	    or the passed arguments.  The
>	    <application>ppp</application> program will wait for the
>	    command to complete before continuing.  Any attempt to
>	    use the PPP link while running the command will appear as
>	    a frozen link.  This is because &man.ppp.8; is
>	    waiting for the command to complete.</para>
>
>	  <para>To execute commands like this, use
>	    <command>!bg</command> instead.  This will execute the
>	    given command in the background, and &man.ppp.8; can
>	    continue to service the link.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-null-modem">
>	  <para>Why does &man.ppp.8; over a null-modem cable never
>	    exit?</para>
>	</question>
>
>	<answer>
>	  <para>There is no way for &man.ppp.8; to automatically
>	    determine that a direct connection has been dropped.  This
>	    is due to the lines that are used in a null-modem serial
>	    cable.  When using this sort of connection, LQR should
>	    always be enabled with the following line:</para>
>
>	  <programlisting>enable lqr</programlisting>
>
>	  <para>LQR is accepted by default if negotiated by the
>	    peer.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-auto-noreasondial">
>	  <para>Why does &man.ppp.8; dial for no reason in
>	    <option>-auto</option> mode?</para>
>	</question>
>
>	<answer>
>	  <para>If &man.ppp.8; is dialing unexpectedly,
>	    determine the cause, and set up dial filters to
>	    prevent such dialing.</para>
>
>	  <para>To determine the cause, use the following line:</para>
>
>	  <programlisting>set log +tcp/ip</programlisting>
>
>	  <para>This will log all traffic through the connection.  The
>	    next time the line comes up unexpectedly, the
>	    reason will be logged with a convenient timestamp next to
>	    it.</para>
>
>	  <para>Next, disable dialing under these circumstances.
>	    Usually, this sort of problem arises due to DNS lookups.
>	    To prevent DNS lookups from establishing a connection
>	    (this will <emphasis>not</emphasis> prevent &man.ppp.8;
>	    from passing the packets through an established
>	    connection), use the following:</para>
>
>	  <programlisting>set dfilter 1 deny udp src eq 53
>set dfilter 2 deny udp dst eq 53
>set dfilter 3 permit 0/0 0/0</programlisting>
>
>	  <para>This is not always suitable, as it will effectively
>	    break demand-dial capabilities.  Most programs
>	    will need a DNS lookup before doing any other network
>	    related things.</para>
>
>	  <para>In the DNS case, try to determine what is actually
>	    trying to resolve a host name.  A lot of the time,
>	    <application>Sendmail</application> is the culprit.  Make
>	    sure to configure <application>Sendmail</application> not
>	    to do any DNS lookups in its configuration file.  See the
>	    section on <link
>	      xlink:href="&url.books.handbook;/smtp-dialup.html">using
>	      email with a dialup connection</link> in the &os;
>	    Handbook for details.  You may
>	    also want to add the following line to
>	    <filename>.mc</filename>:</para>
>
>	  <programlisting>define(`confDELIVERY_MODE', `d')dnl</programlisting>
>
>	  <para>This will make <application>Sendmail</application>
>	    queue everything until the queue is run, usually,
>	    every 30 minutes, or until a <command>sendmail
>	      -q</command> is done, perhaps from
>	    <filename>/etc/ppp/ppp.linkup</filename>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ccp-errors">
>	  <para>What do these CCP errors mean?</para>
>	</question>
>
>	<answer>
>	  <para>I keep seeing the following errors in my log
>	    file:</para>
>
>	  <programlisting>CCP: CcpSendConfigReq
>CCP: Received Terminate Ack (1) state = Req-Sent (6)</programlisting>
>
>	  <para>This is because &man.ppp.8; is trying to negotiate
>	    Predictor1 compression, but the peer does not want to
>	    negotiate any compression at all.  The messages are
>	    harmless, but can be silenced by disabling the
>	    compression:</para>
>
>	  <programlisting>disable pred1</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-connectionspeed">
>	  <para>Why does &man.ppp.8; not log my connection
>	    speed?</para>
>	</question>
>
>	<answer>
>	  <para>To log all lines of the modem
>	    conversation, enable the
>	    following:</para>
>
>	  <programlisting>set log +connect</programlisting>
>
>	  <para>This will make &man.ppp.8; log everything up until the
>	    last requested <quote>expect</quote> string.</para>
>
>	  <para>To see the connect speed when using
>	    PAP or CHAP,
>	    make sure to configure &man.ppp.8; to
>	    expect the whole CONNECT line, using something
>	    like this:</para>
>
>	  <programlisting>set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 4 \
>  \"\" ATZ OK-ATZ-OK ATDT\\T TIMEOUT 60 CONNECT \\c \\n"</programlisting>
>
>	  <para>This gets the CONNECT, sends nothing, then expects a
>	    line-feed, forcing &man.ppp.8; to read the whole CONNECT
>	    response.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ppp-ignores-backslash">
>	  <para>Why does &man.ppp.8; ignore the <literal>\</literal>
>	    character in my chat script?</para>
>	</question>
>
>	<answer>
>	  <para>The <application>ppp</application> utility parses each
>	    line in its configuration files so that it can interpret
>	    strings such as <literal>set phone "123 456 789"</literal>
>	    correctly and realize that the number is actually only
>	    one argument.  To specify a
>	    <literal>&quot;</literal> character, escape it
>	    using a backslash (<literal>\</literal>).</para>
>
>	  <para>When the chat interpreter parses each argument, it
>	    re-interprets the argument to find any special escape
>	    sequences such as <literal>\P</literal> or
>	    <literal>\T</literal>.  As a result
>	    of this double-parsing, remember to use the
>	    correct number of escapes.</para>
>
>	  <para>To actually send a <literal>\</literal>
>	    character, do something
>	    like:</para>
>
>	  <programlisting>set dial "\"\" ATZ OK-ATZ-OK AT\\\\X OK"</programlisting>
>
>	  <para>It will result in the following sequence:</para>
>
>	  <programlisting>ATZ
>OK
>AT\X
>OK</programlisting>
>
>	  <para>Or:</para>
>
>	  <programlisting>set phone 1234567
>set dial "\"\" ATZ OK ATDT\\T"</programlisting>
>
>	  <para>It will result in the following sequence:</para>
>
>	  <programlisting>ATZ
>OK
>ATDT1234567</programlisting>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="fcs-errors">
>	  <para>What are FCS errors?</para>
>	</question>
>
>	<answer>
>	  <para>FCS stands for Frame Check Sequence.  Each PPP packet
>	    has a checksum attached to ensure that the data being
>	    received is the data being sent.  If the FCS of an
>	    incoming packet is incorrect, the packet is dropped and
>	    the HDLC FCS count is increased.  The HDLC error values
>	    can be displayed using the <literal>show hdlc</literal>
>	    command.</para>
>
>	  <para>If the link is bad or if the serial driver is dropping
>	    packets, it will produce the occasional FCS error.
>	    This is not usually worth worrying about although it does
>	    slow down the compression protocols substantially.</para>
>
>	  <para>If the link freezes as soon as it connects and
>	    produces a large number of FCS errors, make sure the modem
>	    is not using software flow control (XON/XOFF).  If the
>	    link must use software flow control, use
>	    <literal>set accmap 0x000a0000</literal> to
>	    tell &man.ppp.8; to escape the <literal>^Q</literal> and
>	    <literal>^S</literal> characters.</para>
>
>	  <para>Another reason for too many FCS errors may be
>	    that the remote end has stopped talking
>	    <acronym>PPP</acronym>.  In this case, enable
>	    <literal>async</literal> logging to
>	    determine if the incoming data is actually a login or
>	    shell prompt.  If it is a shell prompt at the remote
>	    end, it is possible to terminate &man.ppp.8; without
>	    dropping the line by using <command>close lcp</command>
>	    followed by <command>term</command>) to reconnect to
>	    the shell on the remote machine.</para>
>
>	  <para>If nothing in the log file indicates why the link
>	    was terminated, ask the remote
>	    administrator or ISP why the session was
>	    terminated.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="desperation">
>	  <para>None of this helps &mdash; I am desperate!  What can I
>	    do?</para>
>	</question>
>
>	<answer>
>	  <para>If all else fails, send the details of the error, the
>	    configuration files, how &man.ppp.8; is being started, the
>	    relevant parts of the log file, and the
>	    output of <command>netstat -rn</command>, before and after
>	    connecting, to the &a.questions;.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="serial">
>    <title>Serial Communications</title>
>
>    <para>This section answers common questions about serial
>      communications with &os;.  PPP is covered in the <link
>	linkend="networking">Networking</link> section.</para>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="multiport-serial-support">
>	  <para>Which multi-port serial cards are supported by
>	    &os;?</para>
>	</question>
>
>	<answer>
>	  <para>There is a list of these in the <link
>	      xlink:href="&url.books.handbook;/serial.html">Serial
>	      Communications</link> chapter of the Handbook.</para>
>
>	  <para>Most multi-port PCI cards that are based on 16550 or
>	    clones are supported with no extra effort.</para>
>
>	  <para>Some unnamed clone cards have also been known to work,
>	    especially those that claim to be AST compatible.</para>
>
>	  <para>Check &man.uart.4; and &man.sio.4; to get more
>	    information on configuring such cards.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="serial-console-prompt">
>	  <para>How do I get the boot: prompt to show on the serial
>	    console?</para>
>	</question>
>
>	<answer>
>	  <para>See <link
>	      xlink:href="&url.books.handbook;/serialconsole-setup.html">this
>	      section of the Handbook</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="found-serial">
>	  <para>How do I tell if &os; found my serial ports or modem
>	    cards?</para>
>	</question>
>
>	<answer>
>	  <para>As the &os; kernel boots, it will probe for the serial
>	    ports for which the kernel is configured.
>	    Either watch the boot messages closely
>	    or run this command after the system is up and
>	    running:</para>
>
>	  <screen>&prompt.user; <userinput>dmesg | grep -E "^sio[0-9]"</userinput>
>sio0: &lt;16550A-compatible COM port&gt; port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
>sio0: type 16550A
>sio1: &lt;16550A-compatible COM port&gt; port 0x2f8-0x2ff irq 3 on acpi0
>sio1: type 16550A</screen>
>
>	  <para>This example shows two serial ports.  The first is on
>	    IRQ4, port address
>	    <literal>0x3f8</literal>, and has a 16550A-type UART chip.
>	    The second uses the same kind of chip but is on
>	    IRQ3 and is at port address
>	    <literal>0x2f8</literal>.  Internal modem cards are
>	    treated just like serial ports, except that they
>	    always have a modem attached to the
>	    port.</para>
>
>	  <para>The <filename>GENERIC</filename> kernel includes
>	    support for two serial ports using the same IRQ and port
>	    address settings in the above example.  If these settings
>	    are not right for the system, or if there are more modem
>	    cards or serial ports than the kernel is
>	    configured for, reconfigure using the instructions in
>	    <link linkend="make-kernel">building a kernel</link>
>	    for more details.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="access-serial-ports">
>	  <para>How do I access the serial ports on &os;?</para>
>	</question>
>
>	<answer>
>	  <para>The third serial port, <filename>sio2</filename>,
>	    or <filename>COM3</filename>,
>	    is on <filename>/dev/cuad2</filename> for dial-out
>	    devices, and on <filename>/dev/ttyd2</filename> for
>	    dial-in devices.  What is the difference between these two
>	    classes of devices?</para>
>
>	  <para>When
>	    opening <filename>/dev/ttydX</filename> in blocking mode,
>	    a process will wait for the corresponding
>	    <filename>cuadX</filename> device to become inactive, and
>	    then wait for the carrier detect line to go active.  When
>	    the <filename>cuadX</filename> device is opened, it makes
>	    sure the serial port is not already in use by the
>	    <filename>ttydX</filename> device.  If the port is
>	    available, it steals it from the
>	    <filename>ttydX</filename> device.  Also, the
>	    <filename>cuadX</filename> device does not care about
>	    carrier detect.  With this scheme and an auto-answer
>	    modem, remote users can log in and local users can still
>	    dial out with the same modem and the system will take care
>	    of all the conflicts.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="enable-multiport-serial">
>	  <para>How do I enable support for a multi-port serial
>	    card?</para>
>	</question>
>
>	<answer>
>	  <para>The section on kernel configuration provides
>	    information about configuring the kernel.  For a
>	    multi-port serial card, place an &man.sio.4; line for each
>	    serial port on the card in the &man.device.hints.5; file.
>	    But place the IRQ specifiers on only one of the entries.
>	    All of the ports on the card should share one IRQ.  For
>	    consistency, use the last serial port to specify the IRQ.
>	    Also, specify the following option in the kernel
>	    configuration file:</para>
>
>	  <programlisting>options COM_MULTIPORT</programlisting>
>
>	  <para>The following <filename>/boot/device.hints</filename>
>	    example is for an AST 4-port serial card on
>	    IRQ&nbsp;12:</para>
>
>	  <programlisting>hint.sio.4.at="isa"
>hint.sio.4.port="0x2a0"
>hint.sio.4.flags="0x701"
>hint.sio.5.at="isa"
>hint.sio.5.port="0x2a8"
>hint.sio.5.flags="0x701"
>hint.sio.6.at="isa"
>hint.sio.6.port="0x2b0"
>hint.sio.6.flags="0x701"
>hint.sio.7.at="isa"
>hint.sio.7.port="0x2b8"
>hint.sio.7.flags="0x701"
>hint.sio.7.irq="12"</programlisting>
>
>	  <para>The flags indicate that the master port has minor
>	    number <literal>7</literal> (<literal>0x700</literal>),
>	    and all the ports share an IRQ
>	    (<literal>0x001</literal>).</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="default-serial-params">
>	  <para>Can I set the default serial parameters for a
>	    port?</para>
>	</question>
>
>	<answer>
>	  <para>See the <link
>	      xlink:href="&url.books.handbook;/serial.html#serial-hw-config">Serial
>	      Communications</link> section in the &os;
>	    Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="enable-dialup">
>	  <para>How can I enable dialup logins on my modem?</para>
>	</question>
>
>	<answer>
>	  <para>Refer to the section about <link
>	      xlink:href="&url.books.handbook;/dialup.html">Dial-in
>	      Services</link> in the &os; Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="dumb-terminal">
>	  <para>How can I connect a dumb terminal to my &os;
>	    box?</para>
>	</question>
>
>	<answer>
>	  <para>This information is in the <link
>	      xlink:href="&url.books.handbook;/term.html">Terminals</link>
>	    section of the &os; Handbook.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="cannot-tip">
>	  <para>Why can I not run <command>tip</command> or
>	    <command>cu</command>?</para>
>	</question>
>
>	<answer>
>	  <para>The built-in &man.tip.1; and
>	    &man.cu.1; utilities can only access the
>	    <filename>/var/spool/lock</filename> directory via user
>	    <systemitem class="username">uucp</systemitem> and group
>	    <systemitem class="groupname">dialer</systemitem>.
>	    Use the <systemitem
>	      class="groupname">dialer</systemitem> group to control
>	    who has access to the modem or remote systems by adding
>	    user accounts to <systemitem
>	      class="groupname">dialer</systemitem>.</para>
>
>	  <para>Alternatively, everyone can be configured to run
>	    &man.tip.1; and &man.cu.1; by typing:</para>
>
>	  <screen>&prompt.root; <userinput>chmod 4511 /usr/bin/cu</userinput>
>&prompt.root; <userinput>chmod 4511 /usr/bin/tip</userinput></screen>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="misc">
>    <title>Miscellaneous Questions</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="more-swap">
>	  <para>&os; uses a lot of swap space even when the computer
>	    has free memory left.  Why?</para>
>	</question>
>
>	<answer>
>	  <para>&os; will proactively move entirely idle, unused pages
>	    of main memory into swap in order to make more main memory
>	    available for active use.  This heavy use of swap is
>	    balanced by using the extra free memory for
>	    caching.</para>
>
>	  <para>Note that while &os; is proactive in this regard, it
>	    does not arbitrarily decide to swap pages when the system
>	    is truly idle.  Thus, the system will not be all
>	    paged out after leaving it
>	    idle overnight.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="top-freemem">
>	  <para>Why does <command>top</command> show very little free
>	    memory even when I have very few programs running?</para>
>	</question>
>
>	<answer>
>	  <para>The simple answer is that free memory is wasted
>	    memory.  Any memory that programs do not actively
>	    allocate is used within the &os; kernel as disk cache.
>	    The values shown by &man.top.1; labeled as
>	    <literal>Inact</literal>, <literal>Cache</literal>, and
>	    <literal>Buf</literal> are all cached data at different
>	    aging levels.  This cached data means the system does not
>	    have to access a slow disk again for data it has accessed
>	    recently, thus increasing overall performance.  In
>	    general, a low value shown for <literal>Free</literal>
>	    memory in &man.top.1; is good, provided it is not
>	    <emphasis>very</emphasis> low.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="chmod-symlinks">
>	  <para>Why will <command>chmod</command> not change the
>	    permissions on symlinks?</para>
>	</question>
>
>	<answer>
>	  <para>Symlinks do not have permissions, and by default,
>	    &man.chmod.1; will follow symlinks to change the
>	    permissions on the source file, if possible.  For
>	    the file, <filename>foo</filename> with a symlink named
>	    <filename>bar</filename>, this command
>	    will always succeed.</para>
>
>	  <screen>&prompt.user; <userinput>chmod g-w bar</userinput></screen>
>
>	  <para>However, the permissions on <filename>bar</filename>
>	    will not have changed.</para>
>
>	  <para>When changing modes of the file hierarchies rooted in
>	    the files instead of the files themselves, use
>	    either <option>-H</option> or <option>-L</option> together
>	    with <option>-R</option> to make this work.  See
>	    &man.chmod.1; and &man.symlink.7; for more
>	    information.</para>
>
>	  <warning>
>	    <para><option>-R</option> does a
>	      <emphasis>recursive</emphasis> &man.chmod.1;.  Be
>	      careful about specifying directories or symlinks to
>	      directories to &man.chmod.1;.  To change the
>	      permissions of a directory referenced by a symlink, use
>	      &man.chmod.1; without any options and follow the symlink
>	      with a trailing slash (<filename>/</filename>).  For
>	      example, if <filename>foo</filename> is a symlink to
>	      directory <filename>bar</filename>, to
>	      change the permissions of <filename>foo</filename>
>	      (actually <filename>bar</filename>), do
>	      something like:</para>
>
>	    <screen>&prompt.user; <userinput>chmod 555 foo/</userinput></screen>
>
>	    <para>With the trailing slash, &man.chmod.1; will follow
>	      the symlink, <filename>foo</filename>, to change the
>	      permissions of the directory,
>	      <filename>bar</filename>.</para>
>	  </warning>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="dos-binaries">
>	  <para>Can I run DOS binaries under &os;?</para>
>	</question>
>
>	<answer>
>	  <para>Yes.  A DOS emulation program,
>	    <package>emulators/doscmd</package>, is available in the
>	    &os; Ports Collection.</para>
>
>	  <para>If <application>doscmd</application> will not suffice,
>	    <package>emulators/pcemu</package>
>	    emulates an 8088 and enough BIOS services to run many DOS
>	    text-mode applications.  It requires the X Window
>	    System.</para>
>
>	  <para>The Ports Collection also has
>	    <package>emulators/dosbox</package>.  The main focus of
>	    this application is emulating old DOS games using the
>	    local file system for files.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="translation">
>	  <para>What do I need to do to translate a &os; document into
>	    my native language?</para>
>	</question>
>
>	<answer>
>	  <para>See the <link
>	      xlink:href="&url.books.fdp-primer;/translations.html">Translation
>	      <acronym>FAQ</acronym></link> in the &os; Documentation Project
>	    Primer.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="freebsd-mail-bounces">
>	  <para>Why does my email to any address at <systemitem
>	      class="fqdomainname">FreeBSD.org</systemitem>
>	    bounce?</para>
>	</question>
>
>	<answer>
>	  <para>The <systemitem
>	      class="fqdomainname">FreeBSD.org</systemitem> mail
>	    system implements some
>	    <application>Postfix</application> checks on incoming mail
>	    and rejects mail that is either from misconfigured relays
>	    or otherwise appears likely to be spam.  Some of the
>	    specific requirements are: </para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>The IP address of the SMTP client must
>		"reverse-resolve" to a forward confirmed
>		hostname.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>The fully-qualified hostname given in the
>		SMTP conversation (either HELO or EHLO) must resolve
>		to the IP address of the client.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>Other advice to help mail reach its destination
>	    include:</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>Mail should be sent in plain text, and messages
>		sent to mailing lists should generally be no more than
>		200KB in length.</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>Avoid excessive cross posting.  Choose
>		<emphasis>one</emphasis> mailing list which seems most
>		relevant and send it there.</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para>If you still have trouble with email infrastructure at
>	    <systemitem class="fqdomainname">FreeBSD.org</systemitem>,
>	    send a note with the details to
>	    <email>postmaster@freebsd.org</email>;  Include a
>	    date/time interval so that logs may be reviewed &mdash;
>	    and note that we only keep one week's worth of mail logs.
>	    (Be sure to specify the time zone or offset from
>	    UTC.)</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="free-account">
>	  <para>Where can I find a free &os; account?</para>
>	</question>
>
>	<answer>
>	  <para>While &os; does not provide open access to any of
>	    their servers, others do provide open access &unix;
>	    systems.  The charge varies and limited services may be
>	    available.</para>
>
>	  <para><link xlink:href="http://www.arbornet.org/">Arbornet,
>	      Inc</link>, also known as <emphasis>M-Net</emphasis>,
>	    has been providing open access to &unix; systems since
>	    1983.  Starting on an Altos running System III, the site
>	    switched to BSD/OS in 1991.  In June of 2000, the site
>	    switched again to &os;.  <emphasis>M-Net</emphasis> can be
>	    accessed via <application>telnet</application> and
>	    <application>SSH</application> and provides basic access
>	    to the entire &os; software suite.  However, network
>	    access is limited to members and patrons who donate to the
>	    system, which is run as a non-profit organization.
>	    <emphasis>M-Net</emphasis> also provides an bulletin board
>	    system and interactive chat.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="daemon-name">
>	  <para>What is the cute little red guy's name?</para>
>	</question>
>
>	<answer>
>	  <para>He does not have one, and is just called <quote>the
>	      BSD daemon</quote>.  If you insist upon using a name,
>	    call him <quote>beastie</quote>.  Note that
>	    <quote>beastie</quote> is pronounced
>	    <quote>BSD</quote>.</para>
>
>	  <para>More about the BSD daemon is available on his <link
>	      xlink:href="http://www.mckusick.com/beastie/index.html">home
>	      page</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="use-beastie">
>	  <para>Can I use the BSD daemon image?</para>
>	</question>
>
>	<answer>
>	  <para>Perhaps.  The BSD daemon is copyrighted by Marshall
>	    Kirk McKusick.  Check his <link
>	      xlink:href="http://www.mckusick.com/beastie/mainpage/copyright.html">Statement
>	      on the Use of the BSD Daemon Figure</link> for detailed
>	    usage terms.</para>
>
>	  <para>In summary, the image can be used in a tasteful
>	    manner, for personal use, so long as appropriate credit
>	    is given.  Before using the logo commercially, contact
>	    &a.mckusick.email; for permission.  More details are
>	    available on the <link
>	      xlink:href="http://www.mckusick.com/beastie/index.html">BSD
>	      Daemon's home page</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="daemon-images">
>	  <para>Do you have any BSD daemon images I could use?</para>
>	</question>
>
>	<answer>
>	  <para>Xfig and eps drawings are available under
>	    <filename>/usr/share/examples/BSD_daemon/</filename>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="glossary">
>	  <para>I have seen an acronym or other term on the mailing
>	    lists and I do not understand what it means.  Where should
>	    I look?</para>
>	</question>
>
>	<answer>
>	  <para>Refer to the <link
>	      xlink:href="&url.books.handbook;/freebsd-glossary.html">&os;
>	      Glossary</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="bikeshed-painting">
>	  <para>Why should I care what color the bikeshed is?</para>
>	</question>
>
>	<answer>
>	  <para>The really, really short answer is that you should
>	    not.  The somewhat longer answer is that just because you
>	    are capable of building a bikeshed does not mean you
>	    should stop others from building one just because you do
>	    not like the color they plan to paint it.  This is a
>	    metaphor indicating that you need not argue about every
>	    little feature just because you know enough to do so.
>	    Some people have commented that the amount of noise
>	    generated by a change is inversely proportional to the
>	    complexity of the change.</para>
>
>	  <para>The longer and more complete answer is that after a
>	    very long argument about whether &man.sleep.1; should take
>	    fractional second arguments, &a.phk.email; posted a long
>	    message entitled <quote><link
>	      xlink:href="http://www.FreeBSD.org/cgi/getmsg.cgi?fetch=506636+517178+/usr/local/www/db/text/1999/freebsd-hackers/19991003.freebsd-hackers">A
>	      bike shed (any color will do) on greener
>	      grass...</link></quote>.  The appropriate portions of
>	    that message are quoted below.</para>
>
>	  <blockquote>
>	    <attribution>&a.phk.email; on &a.hackers.name;, October 2,
>	      1999</attribution>
>
>	    <para><quote>What is it about this bike shed?</quote>
>	      Some of you have asked me.</para>
>
>	    <para>It is a long story, or rather it is an old story,
>	      but it is quite short actually.  C. Northcote Parkinson
>	      wrote a book in the early 1960s, called
>	      <quote>Parkinson's Law</quote>, which contains a lot of
>	      insight into the dynamics of management.</para>
>
>	    <para><emphasis>[snip a bit of commentary on the
>		book]</emphasis></para>
>
>	    <para>In the specific example involving the bike shed, the
>	      other vital component is an atomic power-plant, I guess
>	      that illustrates the age of the book.</para>
>
>	    <para>Parkinson shows how you can go into the board of
>	      directors and get approval for building a multi-million
>	      or even billion dollar atomic power plant, but if you
>	      want to build a bike shed you will be tangled up in
>	      endless discussions.</para>
>
>	    <para>Parkinson explains that this is because an atomic
>	      plant is so vast, so expensive and so complicated that
>	      people cannot grasp it, and rather than try, they fall
>	      back on the assumption that somebody else checked all
>	      the details before it got this far.  Richard P. Feynmann
>	      gives a couple of interesting, and very much to the
>	      point, examples relating to Los Alamos in his
>	      books.</para>
>
>	    <para>A bike shed on the other hand.  Anyone can build one
>	      of those over a weekend, and still have time to watch
>	      the game on TV.  So no matter how well prepared, no
>	      matter how reasonable you are with your proposal,
>	      somebody will seize the chance to show that he is doing
>	      his job, that he is paying attention, that he is
>	      <emphasis>here</emphasis>.</para>
>
>	    <para>In Denmark we call it <quote>setting your
>		fingerprint</quote>.  It is about personal pride and
>	      prestige, it is about being able to point somewhere and
>	      say <quote>There!  <emphasis>I</emphasis> did
>		that.</quote> It is a strong trait in politicians, but
>	      present in most people given the chance.  Just think
>	      about footsteps in wet cement.</para>
>	  </blockquote>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="funnies">
>    <title>The &os; Funnies</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="very-very-cool">
>	  <para>How cool is &os;?</para>
>	</question>
>
>	<answer>
>	  <para>Q.  Has anyone done any temperature testing while
>	    running &os;?  I know &linux; runs cooler than DOS, but
>	    have never seen a mention of &os;.  It seems to run really
>	    hot.</para>
>
>	  <para>A.  No, but we have done numerous taste tests on
>	    blindfolded volunteers who have also had 250 micrograms of
>	    LSD-25 administered beforehand.  35% of the volunteers
>	    said that &os; tasted sort of orange, whereas &linux;
>	    tasted like purple haze.  Neither group mentioned any
>	    significant variances in temperature.  We eventually had
>	    to throw the results of this survey out entirely anyway
>	    when we found that too many volunteers were wandering out
>	    of the room during the tests, thus skewing the results.
>	    We think most of the volunteers are at Apple now, working
>	    on their new <quote>scratch and sniff</quote> GUI.  It is
>	    a funny old business we are in!</para>
>
>	  <para>Seriously, &os; uses the <acronym>HLT</acronym> (halt)
>	    instruction when the system is idle thus lowering its
>	    energy consumption and therefore the heat it generates.
>	    Also if you have <acronym>ACPI</acronym> (Advanced
>	    Configuration and Power Interface) configured, then &os;
>	    can also put the CPU into a low power mode.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="letmeoutofhere">
>	  <para>Who is scratching in my memory banks??</para>
>	</question>
>
>	<answer>
>	  <para>Q.  Is there anything <quote>odd</quote> that &os;
>	    does when compiling the kernel which would cause the
>	    memory to make a scratchy sound?  When compiling (and for
>	    a brief moment after recognizing the floppy drive upon
>	    startup, as well), a strange scratchy sound emanates from
>	    what appears to be the memory banks.</para>
>
>	  <para>A.  Yes!  You will see frequent references to
>	    <quote>daemons</quote> in the BSD documentation, and what
>	    most people do not know is that this refers to genuine,
>	    non-corporeal entities that now possess your computer.
>	    The scratchy sound coming from your memory is actually
>	    high-pitched whispering exchanged among the daemons as
>	    they best decide how to deal with various system
>	    administration tasks.</para>
>
>	  <para>If the noise gets to you, a good <command>fdisk
>	      /mbr</command> from DOS will get rid of them, but do not
>	    be surprised if they react adversely and try to stop you.
>	    In fact, if at any point during the exercise you hear the
>	    satanic voice of Bill Gates coming from the built-in
>	    speaker, take off running and do not ever look back!
>	    Freed from the counterbalancing influence of the BSD
>	    daemons, the twin demons of DOS and &windows; are often
>	    able to re-assert total control over your machine to the
>	    eternal damnation of your soul.  Now that you know, given
>	    a choice you would probably prefer to get used to the
>	    scratchy noises, no?</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="changing-lightbulbs">
>	  <para>How many &os; hackers does it take to change a
>	    lightbulb?</para>
>	</question>
>
>	<answer>
>	  <para>One thousand, one hundred and sixty-nine:</para>
>
>	  <para>Twenty-three to complain to -CURRENT about the lights
>	    being out;</para>
>
>	  <para>Four to claim that it is a configuration problem, and
>	    that such matters really belong on -questions;</para>
>
>	  <para>Three to submit PRs about it, one of which is misfiled
>	    under doc and consists only of <quote>it's
>	      dark</quote>;</para>
>
>	  <para>One to commit an untested lightbulb which breaks
>	    buildworld, then back it out five minutes later;</para>
>
>	  <para>Eight to flame the PR originators for not including
>	    patches in their PRs;</para>
>
>	  <para>Five to complain about buildworld being broken;</para>
>
>	  <para>Thirty-one to answer that it works for them, and they
>	    must have updated at a bad time;</para>
>
>	  <para>One to post a patch for a new lightbulb to
>	    -hackers;</para>
>
>	  <para>One to complain that he had patches for this three
>	    years ago, but when he sent them to -CURRENT they were
>	    just ignored, and he has had bad experiences with the PR
>	    system; besides, the proposed new lightbulb is
>	    non-reflexive;</para>
>
>	  <para>Thirty-seven to scream that lightbulbs do not belong
>	    in the base system, that committers have no right to do
>	    things like this without consulting the Community, and
>	    WHAT IS -CORE DOING ABOUT IT!?</para>
>
>	  <para>Two hundred to complain about the color of the bicycle
>	    shed;</para>
>
>	  <para>Three to point out that the patch breaks
>	    &man.style.9;;</para>
>
>	  <para>Seventeen to complain that the proposed new lightbulb
>	    is under GPL;</para>
>
>	  <para>Five hundred and eighty-six to engage in a flame war
>	    about the comparative advantages of the GPL, the BSD
>	    license, the MIT license, the NPL, and the personal
>	    hygiene of unnamed FSF founders;</para>
>
>	  <para>Seven to move various portions of the thread to -chat
>	    and -advocacy;</para>
>
>	  <para>One to commit the suggested lightbulb, even though it
>	    shines dimmer than the old one;</para>
>
>	  <para>Two to back it out with a furious flame of a commit
>	    message, arguing that &os; is better off in the dark than
>	    with a dim lightbulb;</para>
>
>	  <para>Forty-six to argue vociferously about the backing out
>	    of the dim lightbulb and demanding a statement from
>	    -core;</para>
>
>	  <para>Eleven to request a smaller lightbulb so it will fit
>	    their Tamagotchi if we ever decide to port &os; to that
>	    platform;</para>
>
>	  <para>Seventy-three to complain about the SNR on -hackers
>	    and -chat and unsubscribe in protest;</para>
>
>	  <para>Thirteen to post <quote>unsubscribe</quote>,
>	    <quote>How do I unsubscribe?</quote>, or <quote>Please
>	      remove me from the list</quote>, followed by the usual
>	    footer;</para>
>
>	  <para>One to commit a working lightbulb while everybody is
>	    too busy flaming everybody else to notice;</para>
>
>	  <para>Thirty-one to point out that the new lightbulb would
>	    shine 0.364% brighter if compiled with TenDRA (although it
>	    will have to be reshaped into a cube), and that &os;
>	    should therefore switch to TenDRA instead of GCC;</para>
>
>	  <para>One to complain that the new lightbulb lacks
>	    fairings;</para>
>
>	  <para>Nine (including the PR originators) to ask <quote>what
>	      is MFC?</quote>;</para>
>
>	  <para>Fifty-seven to complain about the lights being out two
>	    weeks after the bulb has been changed.</para>
>
>	  <para><emphasis>&a.nik.email; adds:</emphasis></para>
>
>	  <para><emphasis>I was laughing quite hard at
>	      this.</emphasis></para>
>
>	  <para><emphasis>And then I thought, <quote>Hang on,
>	      shouldn't there be '1 to document it.' in that list
>	      somewhere?</quote></emphasis></para>
>
>	  <para><emphasis>And then I was enlightened
>	      :-)</emphasis></para>
>
>	  <para><emphasis>&a.tabthorpe.email;</emphasis> says:
>	    <quote>None, <emphasis>real</emphasis> &os; hackers are
>	      not afraid of the dark!</quote></para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="dev-null">
>	  <para>Where does data written to
>	    <filename>/dev/null</filename> go?</para>
>	</question>
>
>	<answer>
>	  <para>It goes into a special data sink in the CPU where it
>	    is converted to heat which is vented through the heatsink
>	    / fan assembly.  This is why CPU cooling is increasingly
>	    important; as people get used to faster processors, they
>	    become careless with their data and more and more of it
>	    ends up in <filename>/dev/null</filename>, overheating
>	    their CPUs.  If you delete <filename>/dev/null</filename>
>	    (which effectively disables the CPU data sink) your CPU
>	    may run cooler but your system will quickly become
>	    constipated with all that excess data and start to behave
>	    erratically.  If you have a fast network connection you
>	    can cool down your CPU by reading data out of
>	    <filename>/dev/random</filename> and sending it off
>	    somewhere; however you run the risk of overheating your
>	    network connection and <filename>/</filename> or angering
>	    your ISP, as most of the data will end up getting
>	    converted to heat by their equipment, but they generally
>	    have good cooling, so if you do not overdo it you should
>	    be OK.</para>
>
>	  <para><emphasis>Paul Robinson adds:</emphasis></para>
>
>	  <para>There are other methods.  As every good sysadmin
>	    knows, it is part of standard practice to send data to the
>	    screen of interesting variety to keep all the pixies that
>	    make up your picture happy.  Screen pixies (commonly
>	    mis-typed or re-named as <quote>pixels</quote>) are
>	    categorized by the type of hat they wear (red, green or
>	    blue) and will hide or appear (thereby showing the color
>	    of their hat) whenever they receive a little piece of
>	    food.  Video cards turn data into pixie-food, and then
>	    send them to the pixies &mdash; the more expensive the
>	    card, the better the food, so the better behaved the
>	    pixies are.  They also need constant stimulation &mdash;
>	    this is why screen savers exist.</para>
>
>	  <para>To take your suggestions further, you could just throw
>	    the random data to console, thereby letting the pixies
>	    consume it.  This causes no heat to be produced at all,
>	    keeps the pixies happy and gets rid of your data quite
>	    quickly, even if it does make things look a bit messy on
>	    your screen.</para>
>
>	  <para>Incidentally, as an ex-admin of a large ISP who
>	    experienced many problems attempting to maintain a stable
>	    temperature in a server room, I would strongly discourage
>	    people sending the data they do not want out to the
>	    network.  The fairies who do the packet switching and
>	    routing get annoyed by it as well.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="punk-my-friend">
>	  <para>My colleague sits at the computer too much, how
>	    can I prank her?</para>
>	</question>
>
>	<answer>
>	  <para>Install <package role="port">games/sl</package> and
>	    wait for her to mistype <userinput>sl</userinput> for
>	    <command>ls</command>.</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="advanced">
>    <title>Advanced Topics</title>
>
>    <qandaset>
>      <qandaentry>
>	<question xml:id="learn-advanced">
>	  <para>How can I learn more about &os;'s internals?</para>
>	</question>
>
>	<answer>
>	  <para>See the <link
>	      xlink:href="&url.books.arch-handbook;">&os;
>	      Architecture Handbook</link>.</para>
>
>	  <para>Additionally, much general &unix; knowledge is
>	    directly applicable to &os;.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="how-to-contribute">
>	  <para>How can I contribute to &os;?</para>
>	</question>
>
>	<answer>
>	  <para>See the article on <link
>	      xlink:href="&url.articles.contributing;/article.html">Contributing
>	      to &os;</link> for specific advice on how to do this.
>	    Assistance is more than welcome!</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="define-snap-release">
>	  <para>What are snapshots and releases?</para>
>	</question>
>
>	<answer>
>	  <para>There are currently &rel.numbranch; active/semi-active
>	    branches in the &os; <link
>	      xlink:href="http://svnweb.FreeBSD.org/base/">Subversion
>	      Repository</link>.  (Earlier branches are only changed
>	    very rarely, which is why there are only &rel.numbranch;
>	    active branches of development):</para>
>
>	  <itemizedlist>
>	    <listitem>
>	      <para>&rel2.releng; AKA
>		&rel2.stable;</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>&rel.releng; AKA
>		&rel.stable;</para>
>	    </listitem>
>
>	    <listitem>
>	      <para>&rel.head.releng; AKA
>		<emphasis>-CURRENT</emphasis> AKA
>		&rel.head;</para>
>	    </listitem>
>	  </itemizedlist>
>
>	  <para><literal>HEAD</literal> is not an actual branch tag.
>	    It is a symbolic constant for
>	    the current, non-branched development
>		stream known as
>	    <emphasis>-CURRENT</emphasis>.</para>
>
>	  <para>Right now, <emphasis>-CURRENT</emphasis> is the
>	    &rel.head.relx; development stream; the &rel.stable;
>	    branch, &rel.releng;, forked off from
>	    <emphasis>-CURRENT</emphasis> in &rel.relengdate; and the
>	    &rel2.stable; branch, &rel2.releng;, forked off from
>	    <emphasis>-CURRENT</emphasis> in &rel2.relengdate;.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="ctm">
>	  <para>Can I follow <emphasis>-CURRENT</emphasis> with
>	    limited Internet access?</para>
>	</question>
>
>	<answer>
>	  <para>Yes, this can be done <emphasis>without</emphasis>
>	    downloading the whole source tree by using the <link
>	      xlink:href="&url.books.handbook;/synching.html#ctm">CTM
>	      facility</link>.</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="submitting-kernel-extensions">
>	  <para>I have written a kernel extension, who do I send it
>	    to?</para>
>	</question>
>
>	<answer>
>	  <para>Take a look at the article on <link
>	      xlink:href="&url.articles.contributing;/article.html">Contributing
>	      to &os;</link> to learn how to submit code.</para>
>
>	  <para>And thanks for the thought!</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="kernel-panic-troubleshooting">
>	  <para>How can I make the most of the data I see when my
>	    kernel panics?</para>
>	</question>
>
>	<answer>
>	  <para>Here is typical kernel panic:</para>
>
>	  <programlisting>Fatal trap 12: page fault while in kernel mode
>fault virtual address   = 0x40
>fault code              = supervisor read, page not present
>instruction pointer     = 0x8:0xf014a7e5
>stack pointer           = 0x10:0xf4ed6f24
>frame pointer           = 0x10:0xf4ed6f28
>code segment            = base 0x0, limit 0xfffff, type 0x1b
>                        = DPL 0, pres 1, def32 1, gran 1
>processor eflags        = interrupt enabled, resume, IOPL = 0
>current process         = 80 (mount)
>interrupt mask          =
>trap number             = 12
>panic: page fault</programlisting>
>
>	  <para>This message is not enough.  While the instruction
>	    pointer value is important, it is also configuration
>	    dependent as it varies depending on the kernel image.
>	    If it is a <filename>GENERIC</filename> kernel
>	    image from one of the snapshots, it is possible for
>	    somebody else to track down the offending function, but
>	    for a custom kernel, only you can tell us where the fault
>	    occurred.</para>
>
>	  <para>To proceed:</para>
>
>	  <procedure>
>	    <step>
>	      <para>Write down the instruction pointer value.  Note
>		that the <literal>0x8:</literal> part at the beginning
>		is not significant in this case: it is the
>		<literal>0xf0xxxxxx</literal> part that we
>		want.</para>
>	    </step>
>
>	    <step>
>	      <para>When the system reboots, do the following:</para>
>
>	      <screen>&prompt.user; <userinput>nm -n kernel.that.caused.the.panic | grep f0xxxxxx</userinput></screen>
>
>	      <para>where <literal>f0xxxxxx</literal> is the
>		instruction pointer value.  The odds are you will not
>		get an exact match since the symbols in the kernel
>		symbol table are for the entry points of functions and
>		the instruction pointer address will be somewhere
>		inside a function, not at the start.  If you do not
>		get an exact match, omit the last digit from the
>		instruction pointer value and try again:</para>
>
>	      <screen>&prompt.user; <userinput>nm -n kernel.that.caused.the.panic | grep f0xxxxx</userinput></screen>
>
>	      <para>If that does not yield any results, chop off
>		another digit.  Repeat until there is some sort of
>		output.  The result will be a possible list of
>		functions which caused the panic.  This is a less than
>		exact mechanism for tracking down the point of
>		failure, but it is better than nothing.</para>
>	    </step>
>	  </procedure>
>
>	  <para>However, the best way to track down the cause of a
>	    panic is by capturing a crash dump, then using
>	    &man.kgdb.1; to generate a stack trace on the crash
>	    dump.</para>
>
>	  <para>In any case, the method is this:</para>
>
>	  <procedure>
>	    <step>
>	      <para>Make sure that the following line is included in
>		the kernel configuration file:</para>
>
>	      <programlisting>makeoptions     DEBUG=-g          # Build kernel with gdb(1) debug symbols</programlisting>
>	    </step>
>
>	    <step>
>	      <para>Change to the <filename>/usr/src</filename>
>		directory:</para>
>
>	      <screen>&prompt.root; <userinput>cd /usr/src</userinput></screen>
>	    </step>
>
>	    <step>
>	      <para>Compile the kernel:</para>
>
>	      <screen>&prompt.root; <userinput>make buildkernel KERNCONF=<replaceable>MYKERNEL</replaceable></userinput></screen>
>	    </step>
>
>	    <step>
>	      <para>Wait for &man.make.1; to finish compiling.</para>
>	    </step>
>
>	    <step>
>	      <screen>&prompt.root; <userinput>make installkernel KERNCONF=MYKERNEL</userinput></screen>
>	    </step>
>
>	    <step>
>	      <para>Reboot.</para>
>	    </step>
>	  </procedure>
>
>	  <note>
>	    <para>If <varname>KERNCONF</varname> is not included,
>	      the <filename>GENERIC</filename> kernel will instead
>	      be built and installed.</para>
>	  </note>
>
>	  <para>The &man.make.1; process will have built two kernels.
>	    <filename>/usr/obj/usr/src/sys/MYKERNEL/kernel</filename>
>	    and
>	    <filename>/usr/obj/usr/src/sys/MYKERNEL/kernel.debug</filename>.
>	    <filename>kernel</filename> was installed as
>	    <filename>/boot/kernel/kernel</filename>, while
>	    <filename>kernel.debug</filename> can be used as the
>	    source of debugging symbols for &man.kgdb.1;.</para>
>
>	  <para>To capture a crash dump, edit
>	    <filename>/etc/rc.conf</filename> and set
>	    <literal>dumpdev</literal> to point to either the swap
>	    partition or <literal>AUTO</literal>.  This will cause the
>	    &man.rc.8; scripts to use the &man.dumpon.8; command to
>	    enable crash dumps.  This command can also be run
>	    manually.  After a panic, the crash dump can be recovered
>	    using &man.savecore.8;; if <literal>dumpdev</literal> is
>	    set in <filename>/etc/rc.conf</filename>, the &man.rc.8;
>	    scripts will run &man.savecore.8; automatically and put
>	    the crash dump in <filename>/var/crash</filename>.</para>
>
>	  <note>
>	    <para>&os; crash dumps are usually the same size as
>	      physical RAM.  Therefore, make sure there is enough
>	      space in <filename>/var/crash</filename> to hold the
>	      dump.  Alternatively, run &man.savecore.8; manually
>	      and have it recover the crash dump to another directory
>	      with more room.  It is possible to limit the
>	      size of the crash dump by using <literal>options
>		MAXMEM=N</literal> where
>	      <replaceable>N</replaceable> is the size of kernel's
>	      memory usage in KBs.  For example, for 1&nbsp;GB
>	      of RAM, limit the kernel's memory usage to
>	      128&nbsp;MB, so that the crash dump size
>	      will be 128&nbsp;MB instead of 1&nbsp;GB.</para>
>	  </note>
>
>	  <para>Once the crash dump has been recovered , get a
>	    stack trace as follows:</para>
>
>	  <screen>&prompt.user; <userinput>kgdb /usr/obj/usr/src/sys/MYKERNEL/kernel.debug /var/crash/vmcore.0</userinput>
><prompt>(kgdb)</prompt> <userinput>backtrace</userinput></screen>
>
>	  <para>Note that there may be several screens worth of
>	    information.  Ideally, use &man.script.1; to
>	    capture all of them.  Using the unstripped kernel image
>	    with all the debug symbols should show the exact line of
>	    kernel source code where the panic occurred.  The stack
>	    trace is usually read from the bottom up to trace
>	    the exact sequence of events that lead to the crash.
>	    &man.kgdb.1; can also be used to print out the contents of
>	    various variables or structures to examine the system
>	    state at the time of the crash.</para>
>
>	  <tip>
>	    <para>If a second computer is available, &man.kgdb.1; can
>	      be configured to do remote debugging, including setting
>	      breakpoints and single-stepping through the kernel
>	      code.</para>
>	  </tip>
>
>	  <note>
>	    <para>If <literal>DDB</literal> is enabled and the
>	      kernel drops into the debugger, a panic
>	      and a crash dump can be forced by typing
>	      <literal>panic</literal> at the <literal>ddb</literal>
>	      prompt.  It may stop in the debugger again during the
>	      panic phase.  If it does, type
>	      <literal>continue</literal> and it will finish the crash
>	      dump.</para>
>	  </note>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="dlsym-failure">
>	  <para>Why has <function>dlsym()</function> stopped working
>	    for ELF executables?</para>
>	</question>
>
>	<answer>
>	  <para>The ELF toolchain does not, by default, make the
>	    symbols defined in an executable visible to the dynamic
>	    linker.  Consequently <function>dlsym()</function>
>	    searches on handles obtained from calls to
>	    <function>dlopen(NULL, flags)</function> will fail to find
>	    such symbols.</para>
>
>	  <para>To search, using
>	    <function>dlsym()</function>, for symbols present in the
>	    main executable of a process, link the
>	    executable using the <option>--export-dynamic</option>
>	    option to the ELF linker (&man.ld.1;).</para>
>	</answer>
>      </qandaentry>
>
>      <qandaentry>
>	<question xml:id="change-kernel-address-space">
>	  <para>How can I increase or reduce the kernel address space
>	    on i386?</para>
>	</question>
>
>	<answer>
>	  <para>By default, the kernel address space is 1&nbsp;GB
>	    (2&nbsp;GB for PAE) for i386.  When running a
>	    network-intensive server or using
>	    ZFS, this will probably not be
>	    enough.</para>
>
>	  <para>Add the following line to the kernel configuration
>	    file to increase available space and rebuild the
>	    kernel:</para>
>
>	  <programlisting>options KVA_PAGES=<replaceable>N</replaceable></programlisting>
>
>	  <para>To find the correct value of
>	    <replaceable>N</replaceable>, divide the desired address
>	    space size (in megabytes) by four.  (For example, it is
>	    <literal>512</literal> for 2&nbsp;GB.)</para>
>	</answer>
>      </qandaentry>
>    </qandaset>
>  </chapter>
>
>  <chapter xml:id="acknowledgments">
>    <title>Acknowledgments</title>
>
>    <para>This innocent little Frequently Asked Questions document has
>      been written, rewritten, edited, folded, spindled, mutilated,
>      eviscerated, contemplated, discombobulated, cogitated,
>      regurgitated, rebuilt, castigated, and reinvigorated over the
>      last decade, by a cast of hundreds if not thousands.
>      Repeatedly.</para>
>
>    <para>We wish to thank every one of the people responsible, and we
>      encourage you to <link
>	xlink:href="&url.articles.contributing;/article.html">join
>	them</link> in making this <acronym>FAQ</acronym> even
>      better.</para>
>  </chapter>
>
>  &bibliography;
></book>

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Attachments on bug 207342: 167184 | 167185