Attachment 55684 Details for Bug 84101 – file.diff

[patch] file.diff

file.diff (text/plain), 10.01 KB, created by Gary W. Swearingen on 2005-07-26 03:00:31 UTC

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Creator: Gary W. Swearingen

Created: 2005-07-26 03:00:31 UTC

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obsolete

>--- mt.orig.1	Mon Jul 25 18:45:15 2005
>+++ mt.1	Mon Jul 25 18:41:54 2005
>@@ -44,30 +44,39 @@
> .Op Fl f Ar tapename
> .Ar command
> .Op Ar count
>+.Nm
>+.Op Fl f Ar tapename
>+.Ar command
>+.Ar argument
> .Sh DESCRIPTION
> The
> .Nm
>-utility is used to give commands to a magnetic tape drive.
>-By default
>-.Nm
>-performs the requested operation once.
>-Operations
>-may be performed multiple times by specifying
>-.Ar count .
>+utility is used to command a magnetic tape drive for operations
>+other than reading or writing data.
>+.Pp
>+The
>+.Fl f
>+option's
>+.Ar tapename
>+overrides the TAPE environment variable described below.
> .Pp
> The available commands are listed below.
> Only as many
> characters as are required to uniquely identify a command
> need be specified.
>-.Bl -tag -width "eof, weof"
>+.Pp
>+The following commands optionally take a
>+.Ar count ,
>+which defaults to 1.
>+.Bl -tag -width "erase"
> .It Cm weof
> Write
> .Ar count
>-end-of-file marks at the current position on the tape.
>+end-of-file (EOF) marks at the current position.
> .It Cm smk
> Write
> .Ar count
>-setmarks at the current position on the tape.
>+setmarks at the current position.
> .It Cm fsf
> Forward space
> .Ar count
>@@ -92,107 +101,111 @@
> Backward space
> .Ar count
> setmarks.
>+.It Cm erase
>+Erase the tape using a long (often very long) method.
>+With a
>+.Ar count
>+of 0, it will erase the tape using a quick method.
>+Operation is not guaranteed if the tape is not at its beginning.
>+The tape will be at its beginning upon completion.
>+.El
>+.Pp
>+The following commands ignore
>+.Ar count .
>+.Bl -tag -width "geteotmodel"
> .It Cm rdhpos
>-Read Hardware block position.
>-Some drives do not support this.
>+Read the hardware block position.
> The block
> number reported is specific for that hardware only.
>-The count argument is
>-ignored.
>-.It Cm rdspos
>-Read SCSI logical block position.
>+With drive data compression especially,
>+this position may have more to do with the amount of data
>+sent to the drive than the amount of data written to tape.
> Some drives do not support this.
>-The
>-count argument is ignored.
>-.It Cm sethpos
>-Set Hardware block position.
>-Some drives do not support this.
>-The count
>-argument is interpreted as a hardware block to which to position the tape.
>-.It Cm setspos
>-Set SCSI logical block position.
>+.It Cm rdspos
>+Read the SCSI logical block position.
>+This typically is greater than the hardware position
>+by the number of end-of-file marks.
> Some drives do not support this.
>-The count
>-argument is interpreted as a SCSI logical block to which to position the tape.
> .It Cm rewind
>-Rewind the tape
>-(Count is ignored).
>+Rewind the tape.
> .It Cm offline , rewoffl
>-Rewind the tape and place the tape unit off-line
>-(Count is ignored).
>-.It Cm erase
>-Erase the tape.
>-A count of 0 disables long erase, which is on by default.
>+Rewind the tape and place the drive off line.
>+Some drives are never off line.
> .It Cm retension
>-Re-tension the tape
>-(one full wind forth and back, Count is ignored).
>+Re-tension the tape.
>+This winds the tape from the current position to the end
>+and then to the beginning.
>+This sometimes improves subsequent reading and writing,
>+particularly for streaming drives.
>+Some drives do not support this.
> .It Cm status
>-Print status information about the tape unit.
>+Output status information about the drive.
> For SCSI magnetic tape devices,
> the current operating modes of density, blocksize, and whether compression
> is enabled is reported.
> The current state of the driver (what it thinks that
> it is doing with the device) is reported.
> If the driver knows the relative
>-position from BOT (in terms of filemarks and records), it prints that.
>+position from BOT (in terms of filemarks and records), it outputs that.
> Note
> that this information is not definitive (only BOT, End of Recorded Media, and
> hardware or SCSI logical block position (if the drive supports such) are
> considered definitive tape positions).
> .It Cm errstat
>-Print (and clear) error status information about this device.
>+Output (and clear) error status information about this device.
> For every normal
> operation (e.g., a read or a write) and every control operation (e.g,, a
> rewind), the driver stores up the last command executed and it is associated
> status and any residual counts (if any).
>-This command retrieves and prints this
>+This command retrieves and outputs this
> information.
> If possible, this also clears any latched error information.
>-.It Cm blocksize
>-Set the block size for the tape unit.
>-Zero means variable-length
>-blocks.
>-.It Cm density
>-Set the density for the tape unit.
>-For the density codes, see below.
>-The density value could be given either numerically, or as a string,
>-corresponding to the
>-.Dq Reference
>-field.
>-If the string is abbreviated, it will be resolved in the order
>-shown in the table, and the first matching entry will be used.
>-If the
>-given string and the resulting canonical density name do not match
>-exactly, an informational message is printed about what the given
>-string has been taken for.
> .It Cm geteotmodel
>-Fetch and print out the current EOT filemark model.
>+Output the current EOT filemark model.
> The model states how
> many filemarks will be written at close if a tape was being written.
>+.It Cm eod , eom
>+Wind the tape to the end of the recorded data,
>+typically after an EOF mark where another file may be written.
>+.El
>+.Pp
>+The following commands require an
>+.Ar argument .
>+.Bl -tag -width "seteotmodel"
>+.It Cm sethpos
>+Set the hardware block position.
>+The
>+.Ar argument
>+is a hardware block number to which to position the tape.
>+Some drives do not support this.
>+.It Cm setspos
>+Set the SCSI logical block position.
>+The
>+.Ar argument
>+is a SCSI logical block number to which to position the tape.
>+Some drives do not support this.
>+.It Cm blocksize
>+Set the block size for the drive.
>+The
>+.Ar argument
>+is the number of bytes per block,
>+except 0 commands the drive to use variable-length blocks.
> .It Cm seteotmodel
>-Set (from the
>-.Ar count
>-argument)
>-and print out the current and EOT filemark model.
>-Typically this will be
>-.Ar 2
>+Set the EOT filemark model to
>+.Ar argument
>+and output the old and new models.
>+Typically this will be 2
> filemarks, but some devices (typically QIC cartridge drives) can
>-only write
>-.Ar 1
>-filemark.
>-Currently you can only choose a value of
>+only write 1 filemark.
>+You may only choose a value of
> .Ar 1
> or
> .Ar 2 .
>-.It Cm eom
>-Forward space to end of recorded medium
>-(Count is ignored).
>-.It Cm eod
>-Forward space to end of data, identical to
>-.Cm eom .
> .It Cm comp
>-Set compression mode.
>-There are currently several possible values for the compression mode:
>+Set the drive's compression mode.
>+The non-numeric values of
>+.Ar argument
>+are:
> .Pp
> .Bl -tag -width 9n -compact
> .It off
>@@ -212,7 +225,7 @@
> .El
> .Pp
> In addition to the above recognized compression keywords, the user can
>-supply a numeric compression algorithm for the tape drive to use.
>+supply a numeric compression algorithm for the drive to use.
> In most
> cases, simply turning the compression
> .Sq on
>@@ -222,31 +235,32 @@
> .Cm status
> display to see which compression algorithm is currently in use), the user
> can manually specify one of the supported compression keywords (above), or
>-supply a numeric compression value.
>+supply a numeric compression value from the drive's specifications.
>+.It Cm density
>+Set the density for the drive.
>+For the density codes, see below.
>+The density value could be given either numerically, or as a string,
>+corresponding to the
>+.Dq Reference
>+field.
>+If the string is abbreviated, it will be resolved in the order
>+shown in the table, and the first matching entry will be used.
>+If the
>+given string and the resulting canonical density name do not match
>+exactly, an informational message is output about what the given
>+string has been taken for.
> .El
> .Pp
>-If a tape name is not specified, and the environment variable
>-.Ev TAPE
>-does not exist;
>-.Nm
>-uses the device
>-.Pa /dev/nsa0 .
>-.Pp
>-The
>-.Nm
>-utility returns a 0 exit status when the operation(s) were successful,
>-1 if the command was unrecognized, and 2 if an operation failed.
>-.Pp
> The following density table was taken from the
> .Sq Historical sequential access density codes
> table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC)
> working draft, dated November 11, 1997.
> .Pp
>-The different density codes are as follows:
>-.Pp
>-.Dl "0x0	default for device
>-.Dl "0xE	reserved for ECMA
>+The density codes are:
> .Bd -literal -offset 3n
>+0x0    default for device
>+0xE    reserved for ECMA
>+.Dl ""
> Value  Width        Tracks    Density         Code Type Reference   Note
>         mm    in              bpmm       bpi
> 0x01   12.7  (0.5)    9         32     (800)  NRZI  R   X3.22-1983   2
>@@ -320,18 +334,14 @@
>    8 physical tracks each.
> .Ed
> .Sh ENVIRONMENT
>-If the following environment variable exists, it is utilized by
>-.Nm .
>-.Bl -tag -width Fl
>+.Bl -tag -width TAPE
> .It Ev TAPE
>-The
>-.Nm
>-utility checks the
>-.Ev TAPE
>-environment variable if the
>-argument
>-.Ar tapename
>-is not given.
>+This is the -pathname of the tape drive.
>+The default (if the variable is unset, but not if it is null) is
>+.Pa /dev/nsa0 .
>+It may be overridden with the
>+.Fl f
>+option.
> .El
> .Sh FILES
> .Bl -tag -width /dev/*sa[0-9]*xx -compact
>@@ -340,6 +350,13 @@
> .It Pa /dev/*sa[0-9]*
> SCSI magnetic tape interface
> .El
>+.Sh DIAGNOSTICS
>+.Pp
>+The exit status will be 0 when the drive operations were successful,
>+2 when the drive operations were unsuccessful, and 1 for other
>+problems like an unrecognized command or a missing drive device.
>+.Sh COMPATIBILITY
>+Some undocumented commands support old software.
> .Sh SEE ALSO
> .Xr dd 1 ,
> .Xr ioctl 2 ,
>@@ -373,3 +390,14 @@
> since it was often confused with
> .Cm eom ,
> which is fairly dangerous.
>+.Sh BUGS
>+The utility cannot be interrupted or killed during a long erase
>+(which can be longer than an hour), and it is easy to forget
>+that the default erase is long.
>+.Pp
>+Hardware block numbers do not always correspond to blocks on the tape
>+when the drive uses internal compression.
>+.Pp
>+Erasure is not guaranteed if the tape is not at its beginning.
>+.Pp
>+Tape-related documentation is poor, here and elsewhere.

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Attachments on bug 84101: 55684