43518607b2
The primary focus of these changes is to modernize FreeBSD's
tape infrastructure so that we can take advantage of some of the
features of modern tape drives and allow support for LTFS.
Significant changes and new features include:
o sa(4) driver status and parameter information is now exported via an
XML structure. This will allow for changes and improvements later
on that will not break userland applications. The old MTIOCGET
status ioctl remains, so applications using the existing interface
will not break.
o 'mt status' now reports drive-reported tape position information
as well as the previously available calculated tape position
information. These numbers will be different at times, because
the drive-reported block numbers are relative to BOP (Beginning
of Partition), but the block numbers calculated previously via
sa(4) (and still provided) are relative to the last filemark.
Both numbers are now provided. 'mt status' now also shows the
drive INQUIRY information, serial number and any position flags
(BOP, EOT, etc.) provided with the tape position information.
'mt status -v' adds information on the maximum possible I/O size,
and the underlying values used to calculate it.
o The extra sa(4) /dev entries (/dev/saN.[0-3]) have been removed.
The extra devices were originally added as place holders for
density-specific device nodes. Some OSes (NetBSD, NetApp's OnTap
and Solaris) have had device nodes that, when you write to them,
will automatically select a given density for particular tape drives.
This is a convenient way of switching densities, but it was never
implemented in FreeBSD. Only the device nodes were there, and that
sometimes confused users.
For modern tape devices, the density is generally not selectable
(e.g. with LTO) or defaults to the highest availble density when
the tape is rewritten from BOT (e.g. TS11X0). So, for most users,
density selection won't be necessary. If they do need to select
the density, it is easy enough to use 'mt density' to change it.
o Protection information is now supported. This is either a
Reed-Solomon CRC or CRC32 that is included at the end of each block
read and written. On write, the tape drive verifies the CRC, and
on read, the tape drive provides a CRC for the userland application
to verify.
o New, extensible tape driver parameter get/set interface.
o Density reporting information. For drives that support it,
'mt getdensity' will show detailed information on what formats the
tape drive supports, and what formats the tape drive supports.
o Some mt(1) functionality moved into a new mt(3) library so that
external applications can reuse the code.
o The new mt(3) library includes helper routines to aid in parsing
the XML output of the sa(4) driver, and build a tree of driver
metadata.
o Support for the MTLOAD (load a tape in the drive) and MTWEOFI
(write filemark immediate) ioctls needed by IBM's LTFS
implementation.
o Improve device departure behavior for the sa(4) driver. The previous
implementation led to hangs when the device was open.
o This has been tested on the following types of drives:
IBM TS1150
IBM TS1140
IBM LTO-6
IBM LTO-5
HP LTO-2
Seagate DDS-4
Quantum DLT-4000
Exabyte 8505
Sony DDS-2
contrib/groff/tmac/doc-syms,
share/mk/bsd.libnames.mk,
lib/Makefile,
Add libmt.
lib/libmt/Makefile,
lib/libmt/mt.3,
lib/libmt/mtlib.c,
lib/libmt/mtlib.h,
New mt(3) library that contains functions moved from mt(1) and
new functions needed to interact with the updated sa(4) driver.
This includes XML parser helper functions that application writers
can use when writing code to query tape parameters.
rescue/rescue/Makefile:
Add -lmt to CRUNCH_LIBS.
src/share/man/man4/mtio.4
Clarify this man page a bit, and since it contains what is
essentially the mtio.h header file, add new ioctls and structure
definitions from mtio.h.
src/share/man/man4/sa.4
Update BUGS and maintainer section.
sys/cam/scsi/scsi_all.c,
sys/cam/scsi/scsi_all.h:
Add SCSI SECURITY PROTOCOL IN/OUT CDB definitions and CDB building
functions.
sys/cam/scsi/scsi_sa.c
sys/cam/scsi/scsi_sa.h
Many tape driver changes, largely outlined above.
Increase the sa(4) driver read/write timeout from 4 to 32
minutes. This is based on the recommended values for IBM LTO
5/6 drives. This may also avoid timeouts for other tape
hardware that can take a long time to do retries and error
recovery. Longer term, a better way to handle this is to ask
the drive for recommended timeout values using the REPORT
SUPPORTED OPCODES command. Modern IBM and Oracle tape drives
at least support that command, and it would allow for more
accurate timeout values.
Add XML status generation. This is done with a series of
macros to eliminate as much duplicate code as possible. The
new XML-based status values are reported through the new
MTIOCEXTGET ioctl.
Add XML driver parameter reporting, using the new MTIOCPARAMGET
ioctl.
Add a new driver parameter setting interface, using the new
MTIOCPARAMSET and MTIOCSETLIST ioctls.
Add a new MTIOCRBLIM ioctl to get block limits information.
Add CCB/CDB building routines scsi_locate_16, scsi_locate_10,
and scsi_read_position_10().
scsi_locate_10 implements the LOCATE command, as does the
existing scsi_set_position() command. It just supports
additional arguments and features. If/when we figure out a
good way to provide backward compatibility for older
applications using the old function API, we can just revamp
scsi_set_position(). The same goes for
scsi_read_position_10() and the existing scsi_read_position()
function.
Revamp sasetpos() to take the new mtlocate structure as an
argument. It now will use either scsi_locate_10() or
scsi_locate_16(), depending upon the arguments the user
supplies. As before, once we change position we don't have a
clear idea of what the current logical position of the tape
drive is.
For tape drives that support long form position data, we
read the current position and store that for later reporting
after changing the position. This should help applications
like Bacula speed tape access under FreeBSD once they are
modified to support the new ioctls.
Add a new quirk, SA_QUIRK_NO_LONG_POS, that is set for all
drives that report SCSI-2 or older, as well as drives that
report an Illegal Request type error for READ POSITION with
the long format. So we should automatically detect drives
that don't support the long form and stop asking for it after
an initial try.
Add a partition number to the sa(4) softc.
Improve device departure handling. The previous implementation
led to hangs when the device was open.
If an application had the sa(4) driver open, and attempted to
close it after it went away, the cam_periph_release() call in
saclose() would cause the periph to get destroyed because that
was the last reference to it. Because destroy_dev() was
called from the sa(4) driver's cleanup routine (sacleanup()),
and would block waiting for the close to happen, a deadlock
would result.
So instead of calling destroy_dev() from the cleanup routine,
call destroy_dev_sched_cb() from saoninvalidate() and wait for
the callback.
Acquire a reference for devfs in saregister(), and release it
in the new sadevgonecb() routine when all devfs devices for
the particular sa(4) driver instance are gone.
Add a new function, sasetupdev(), to centralize setting
per-instance devfs device parameters instead of repeating the
code in saregister().
Add an open count to the softc, so we know how many
peripheral driver references are a result of open
sessions.
Add the D_TRACKCLOSE flag to the cdevsw flags so
that we get a 1:1 mapping of open to close calls
instead of a N:1 mapping.
This should be a no-op for everything except the
control device, since we don't allow more than one
open on non-control devices.
However, since we do allow multiple opens on the
control device, the combination of the open count
and the D_TRACKCLOSE flag should result in an
accurate peripheral driver reference count, and an
accurate open count.
The accurate open count allows us to release all
peripheral driver references that are the result
of open contexts once we get the callback from devfs.
sys/sys/mtio.h:
Add a number of new mt(4) ioctls and the requisite data
structures. None of the existing interfaces been removed
or changed.
This includes definitions for the following new ioctls:
MTIOCRBLIM /* get block limits */
MTIOCEXTLOCATE /* seek to position */
MTIOCEXTGET /* get tape status */
MTIOCPARAMGET /* get tape params */
MTIOCPARAMSET /* set tape params */
MTIOCSETLIST /* set N params */
usr.bin/mt/Makefile:
mt(1) now depends on libmt, libsbuf and libbsdxml.
usr.bin/mt/mt.1:
Document new mt(1) features and subcommands.
usr.bin/mt/mt.c:
Implement support for mt(1) subcommands that need to
use getopt(3) for their arguments.
Implement a new 'mt status' command to replace the old
'mt status' command. The old status command has been
renamed 'ostatus'.
The new status function uses the MTIOCEXTGET ioctl, and
therefore parses the XML data to determine drive status.
The -x argument to 'mt status' allows the user to dump out
the raw XML reported by the kernel.
The new status display is mostly the same as the old status
display, except that it doesn't print the redundant density
mode information, and it does print the current partition
number and position flags.
Add a new command, 'mt locate', that will supersede the
old 'mt setspos' and 'mt sethpos' commands. 'mt locate'
implements all of the functionality of the MTIOCEXTLOCATE
ioctl, and allows the user to change the logical position
of the tape drive in a number of ways. (Partition,
block number, file number, set mark number, end of data.)
The immediate bit and the explicit address bits are
implemented, but not documented in the man page.
Add a new 'mt weofi' command to use the new MTWEOFI ioctl.
This allows the user to ask the drive to write a filemark
without waiting around for the operation to complete.
Add a new 'mt getdensity' command that gets the XML-based
tape drive density report from the sa(4) driver and displays
it. This uses the SCSI REPORT DENSITY SUPPORT command
to get comprehensive information from the tape drive about
what formats it is able to read and write.
Add a new 'mt protect' command that allows getting and setting
tape drive protection information. The protection information
is a CRC tacked on to the end of every read/write from and to
the tape drive.
Sponsored by: Spectra Logic
MFC after: 1 month
624 lines
22 KiB
Groff
624 lines
22 KiB
Groff
.\" Copyright (c) 1981, 1990, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)mt.1 8.1 (Berkeley) 6/6/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd February 12, 2014
|
|
.Dt MT 1
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mt
|
|
.Nd magnetic tape manipulating program
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.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 command a magnetic tape drive for operations
|
|
other than reading or writing data.
|
|
.Pp
|
|
The
|
|
.Fl f
|
|
option's
|
|
.Ar tapename
|
|
overrides the
|
|
.Ev 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.
|
|
.Pp
|
|
The following commands optionally take a
|
|
.Ar count ,
|
|
which defaults to 1.
|
|
.Bl -tag -width ".Cm erase"
|
|
.It Cm weof
|
|
Write
|
|
.Ar count
|
|
end-of-file (EOF) marks at the current position.
|
|
This returns when the file mark has been written to the media.
|
|
.It Cm weofi
|
|
Write
|
|
.Ar count
|
|
end-of-file (EOF) marks at the current position.
|
|
This returns as soon as the command has been validated by the tape drive.
|
|
.It Cm smk
|
|
Write
|
|
.Ar count
|
|
setmarks at the current position (DDS drives only).
|
|
.It Cm fsf
|
|
Forward space
|
|
.Ar count
|
|
files.
|
|
.It Cm fsr
|
|
Forward space
|
|
.Ar count
|
|
records.
|
|
.It Cm fss
|
|
Forward space
|
|
.Ar count
|
|
setmarks (DDS drives only).
|
|
.It Cm bsf
|
|
Backward space
|
|
.Ar count
|
|
files.
|
|
.It Cm bsr
|
|
Backward space
|
|
.Ar count
|
|
records.
|
|
.It Cm bss
|
|
Backward space
|
|
.Ar count
|
|
setmarks (DDS drives only).
|
|
.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 ".Cm geteotmodel"
|
|
.It Cm rdhpos
|
|
Read the hardware block position.
|
|
The block
|
|
number reported is specific for that hardware only.
|
|
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.
|
|
.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.
|
|
.It Cm rewind
|
|
Rewind the tape.
|
|
.It Cm offline , rewoffl
|
|
Rewind the tape and place the drive off line.
|
|
Some drives are never off line.
|
|
.It Cm load
|
|
Load the tape into the drive.
|
|
.It Cm retension
|
|
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 ostatus
|
|
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 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).
|
|
.Pp
|
|
Also note that this is the old status command, and will be eliminated in
|
|
favor of the new status command (see below) in a future release.
|
|
.It Cm errstat
|
|
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 outputs this
|
|
information.
|
|
If possible, this also clears any latched error information.
|
|
.It Cm geteotmodel
|
|
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.
|
|
.It Cm rblim
|
|
Report the block limits of the tape drive, including the minimum and
|
|
maximum block size, and the block granularity if any.
|
|
.El
|
|
.Pp
|
|
The following commands may require an
|
|
.Ar argument .
|
|
.Bl -tag -width ".Cm 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 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 1 filemark.
|
|
You may only choose a value of
|
|
.Ar 1
|
|
or
|
|
.Ar 2 .
|
|
.It Cm status
|
|
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.
|
|
.Pp
|
|
If the driver knows the relative
|
|
position from BOT (in terms of filemarks and records), it outputs that.
|
|
If the tape drive supports the long form report of the
|
|
.Tn SCSI
|
|
READ POSITION command, the Reported File Number and Reported Record Number
|
|
will be numbers other than -1, and there may be Flags reported as well.
|
|
.Pp
|
|
The BOP flag means that the logical position of the drive is at the
|
|
beginning of the partition.
|
|
.Pp
|
|
The EOP flag means that the logical position of the drive is between Early
|
|
Warning and End of Partition.
|
|
.Pp
|
|
The BPEW flag means that the logical position of the drive is in a
|
|
Programmable Early Warning Zone or on the EOP side of Early Warning.
|
|
.Pp
|
|
Note that the Reported Record Number is the tape block or object number
|
|
relative to the beginning of the partition.
|
|
The Calculated Record Number is the tape block or object number relative
|
|
to the previous file mark.
|
|
.Pp
|
|
Note
|
|
that the Calculated File and Record Numbers are not definitive.
|
|
The Reported File and Record Numbers are definitive, if they are numbers
|
|
other than -1.
|
|
.Bl -tag -width 6n
|
|
.It Fl v
|
|
Print additional status information, such as the maximum supported I/O
|
|
size.
|
|
.It Fl x
|
|
Print all available status data to stdout in XML format.
|
|
.El
|
|
.It Cm getdensity
|
|
Report density support information for the tape drive and any media that is
|
|
loaded.
|
|
Most drives will report at least basic density information similar to that
|
|
reported by
|
|
.Nm status
|
|
command.
|
|
Newer tape drives that conform to the T-10 SSC and newer tape
|
|
specifications may report more detailed information about the types of
|
|
tapes they support and the tape currently in the drive.
|
|
.Bl -tag -width 6n
|
|
.It Fl x
|
|
Print all available density data to stdout in XML format.
|
|
Because density information is currently included in the general status XML
|
|
report used for
|
|
.Nm
|
|
status command, this will be the same XML output via
|
|
.Do
|
|
.Nm
|
|
status
|
|
.Fl x
|
|
.Dc
|
|
.El
|
|
.It Cm param
|
|
Display or set parameters.
|
|
One of
|
|
.Fl l ,
|
|
.Fl s ,
|
|
or
|
|
.Fl x
|
|
must be specified to indicate which operation to perform.
|
|
.Bl -tag -width 8n
|
|
.It Fl l
|
|
List parameters, values and descriptions.
|
|
By default all parameters will be displayed.
|
|
To display a specific parameter, specify the parameter with
|
|
.Fl p .
|
|
.It Fl p Ar name
|
|
Specify the parameter name to list (with
|
|
.Fl l )
|
|
or set (with
|
|
.Fl s ) .
|
|
.It Fl q
|
|
Enable quiet mode for parameter listing.
|
|
This will suppress printing of parameter descriptions.
|
|
.It Fl s Ar value
|
|
Specify the parameter value to set.
|
|
The general type of this argument (integer, unsigned integer, string) is
|
|
determined by the type of the variable indicated by the
|
|
.Xr sa 4
|
|
driver.
|
|
More detailed argument checking is done by the
|
|
.Xr sa 4
|
|
driver.
|
|
.It Fl x
|
|
Print out all parameter information in XML format.
|
|
.El
|
|
.It Cm protect
|
|
Display or set drive protection parameters.
|
|
This is used to control checking and reporting a per-block checksum for
|
|
tape drives that support it.
|
|
Some drives may only support some parameters.
|
|
.Bl -tag -width 8n
|
|
.It Fl b Ar 0|1
|
|
Set the Recover Buffered Data Protected bit.
|
|
If set, this indicates that checksums are transferred with the logical
|
|
blocks transferred by the RECOVERED BUFFERED DATA
|
|
.Tn SCSI
|
|
command.
|
|
.It Fl d
|
|
Disable all protection information settings.
|
|
.It Fl e
|
|
Enable all protection information settings.
|
|
The default protection method used is Reed-Solomon CRC (protection method
|
|
1), as specified in ECMA-319.
|
|
The default protection information length used with Reed-Solomon CRC is
|
|
4 bytes.
|
|
To enable all settings except one more more settings, specify the
|
|
.Fl e
|
|
argument and then explicitly disable settings that you do not wish to
|
|
enable.
|
|
For example, specifying
|
|
.Fl e
|
|
.Fl w Ar 0
|
|
will enable all settings except for LBP_W.
|
|
.It Fl l
|
|
List available protection parmeters and their current settings.
|
|
.It Fl L Ar len
|
|
Set the length of the protection information in bytes.
|
|
For Reed-Solomon CRC, the protection information length should be 4 bytes.
|
|
.It Fl m Ar num
|
|
Specify the numeric value for the protection method.
|
|
The numeric value for Reed-Solomon CRC is 1.
|
|
.It Fl r Ar 0|1
|
|
Set the LBP_R parameter.
|
|
When set, this indicates that each block read from the tape drive will
|
|
have a checksum at the end.
|
|
.It Fl v
|
|
Enable verbose mode for parameter listing.
|
|
This will include descriptions of each parameter.
|
|
.It Fl w Ar 0|1
|
|
Set the LBP_W parameter.
|
|
When set, this indicates that each block written to the tape drive will have
|
|
a checksum at the end.
|
|
The drive will verify the checksum before writing the block to tape.
|
|
.El
|
|
.It Cm locate
|
|
Set the tape drive's logical position.
|
|
One of
|
|
.Fl b ,
|
|
.Fl e ,
|
|
.Fl f ,
|
|
or
|
|
.Fl s
|
|
must be specified to indicate the type of position.
|
|
If the partition number is specified, the drive will first relocate to the
|
|
given partition (if it exists) and then to the position indicated within
|
|
that partition.
|
|
If the partition number is not specified, the drive will relocate to the
|
|
given position within the current partition.
|
|
.Bl -tag -width 14n
|
|
.It Fl b Ar block_addr
|
|
Relocate to the given tape block or logical object identifier.
|
|
Note that the block number is the Reported Record Number that is relative
|
|
to the beginning of the partition (or beginning of tape).
|
|
.It Fl e
|
|
Relocate to the end of data.
|
|
.It Fl f Ar fileno
|
|
Relocate to the given file number.
|
|
.It Fl p Ar partition
|
|
Specify the partition to change to.
|
|
.It Fl s Ar setmark
|
|
Relocate to the given set mark.
|
|
.El
|
|
.It Cm comp
|
|
Set the drive's compression mode.
|
|
The non-numeric values of
|
|
.Ar argument
|
|
are:
|
|
.Pp
|
|
.Bl -tag -width 9n -compact
|
|
.It off
|
|
Turn compression off.
|
|
.It on
|
|
Turn compression on.
|
|
.It none
|
|
Same as
|
|
.Ar off .
|
|
.It enable
|
|
Same as
|
|
.Ar on .
|
|
.It IDRC
|
|
IBM Improved Data Recording Capability compression (0x10).
|
|
.It DCLZ
|
|
DCLZ compression algorithm (0x20).
|
|
.El
|
|
.Pp
|
|
In addition to the above recognized compression keywords, the user can
|
|
supply a numeric compression algorithm for the drive to use.
|
|
In most
|
|
cases, simply turning the compression
|
|
.Sq on
|
|
will have the desired effect of enabling the default compression algorithm
|
|
supported by the drive.
|
|
If this is not the case (see the
|
|
.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 from the drive's specifications.
|
|
.Pp
|
|
Note that for some older tape drives (for example the Exabyte 8200 and 8500
|
|
series drives) it is necessary to switch to a different density to tell the
|
|
drive to record data in its compressed format.
|
|
If the user attempts to turn compression on while the uncompressed density
|
|
is selected, the drive will return an error.
|
|
This is generally not an issue for modern tape drives.
|
|
.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
|
|
The initial version of the density table below 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.
|
|
Subsequent additions have come from a number of sources.
|
|
.Pp
|
|
The density codes are:
|
|
.Bd -literal -offset 2n
|
|
0x0 default for device
|
|
0xE reserved for ECMA
|
|
|
|
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
|
|
0x02 12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2
|
|
0x03 12.7 (0.5) 9 246 (6,250) GCR R X3.54-1986 2
|
|
0x05 6.3 (0.25) 4/9 315 (8,000) GCR C X3.136-1986 1
|
|
0x06 12.7 (0.5) 9 126 (3,200) PE R X3.157-1987 2
|
|
0x07 6.3 (0.25) 4 252 (6,400) IMFM C X3.116-1986 1
|
|
0x08 3.81 (0.15) 4 315 (8,000) GCR CS X3.158-1987 1
|
|
0x09 12.7 (0.5) 18 1,491 (37,871) GCR C X3.180 2
|
|
0x0A 12.7 (0.5) 22 262 (6,667) MFM C X3B5/86-199 1
|
|
0x0B 6.3 (0.25) 4 63 (1,600) PE C X3.56-1986 1
|
|
0x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1 1,6
|
|
0x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2 1,6
|
|
0x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120 1,6
|
|
0x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150 1,6
|
|
0x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320 1,6
|
|
0x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350 1,6
|
|
0x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A 5
|
|
0x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5,11
|
|
0x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5,12
|
|
0x16 12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1
|
|
0x17 12.7 (0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1
|
|
0x18 12.7 (0.5) 112 1,673 (42,500) MFM C X3B5/92-50 1
|
|
0x19 12.7 (0.5) 128 2,460 (62,500) RLL C DLTapeIII 6,7
|
|
0x1A 12.7 (0.5) 128 3,214 (81,633) RLL C DLTapeIV(20) 6,7
|
|
0x1B 12.7 (0.5) 208 3,383 (85,937) RLL C DLTapeIV(35) 6,7
|
|
0x1C 6.3 (0.25) 34 1,654 (42,000) MFM C QIC-385M 1,6
|
|
0x1D 6.3 (0.25) 32 1,512 (38,400) GCR C QIC-410M 1,6
|
|
0x1E 6.3 (0.25) 30 1,385 (36,000) GCR C QIC-1000C 1,6
|
|
0x1F 6.3 (0.25) 30 2,666 (67,733) RLL C QIC-2100C 1,6
|
|
0x20 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-6GB(M) 1,6
|
|
0x21 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-20GB(C) 1,6
|
|
0x22 6.3 (0.25) 42 1,600 (40,640) GCR C QIC-2GB(C) ?
|
|
0x23 6.3 (0.25) 38 2,666 (67,733) RLL C QIC-875M ?
|
|
0x24 3.81 (0.15) 1 2,400 (61,000) CS DDS-2 5
|
|
0x25 3.81 (0.15) 1 3,816 (97,000) CS DDS-3 5
|
|
0x26 3.81 (0.15) 1 3,816 (97,000) CS DDS-4 5
|
|
0x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth 5
|
|
0x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224 1
|
|
0x29 12.7 (0.5)
|
|
0x2A
|
|
0x2B 12.7 (0.5) 3 ? ? ? C X3.267 5
|
|
0x40 12.7 (0.5) 384 4,800 (123,952) C LTO-1
|
|
0x41 12.7 (0.5) 208 3,868 (98,250) RLL C DLTapeIV(40) 6,7
|
|
0x42 12.7 (0.5) 512 7,398 (187,909) C LTO-2
|
|
0x44 12.7 (0.5) 704 9,638 (244,805) C LTO-3
|
|
0x46 12.7 (0.5) 896 12,725 (323,215) C LTO-4
|
|
0x48 12.7 (0.5) 448 5,236 (133,000) PRML C SDLTapeI(110) 6,8
|
|
0x49 12.7 (0.5) 448 7,598 (193,000) PRML C SDLTapeI(160) 6,8
|
|
0x4A 12.7 (0.5) 768 ? C T10000A 10
|
|
0x4B 12.7 (0.5) 1152 ? C T10000B 10
|
|
0x4C 12.7 (0.5) 3584 ? C T10000C 10
|
|
0x4D 12.7 (0.5) 4608 ? C T10000D 10
|
|
0x51 12.7 (0.5) 512 11,800 (299,720) C 3592A1 (unencrypted)
|
|
0x52 12.7 (0.5) 896 11,800 (299,720) C 3592A2 (unencrypted)
|
|
0x53 12.7 (0.5) 1152 13,452 (341,681) C 3592A3 (unencrypted)
|
|
0x54 12.7 (0.5) 2560 19,686 (500,024) C 3592A4 (unencrypted)
|
|
0x55 12.7 (0.5) 5120 20,670 (525,018) C 3592A5 (unencrypted)
|
|
0x58 12.7 (0.5) 1280 15,142 (384,607) C LTO-5
|
|
0x5A 12.7 (0.5) 2176 15,142 (384,607) C LTO-6
|
|
0x71 12.7 (0.5) 512 11,800 (299,720) C 3592A1 (encrypted)
|
|
0x72 12.7 (0.5) 896 11,800 (299,720) C 3592A2 (encrypted)
|
|
0x73 12.7 (0.5) 1152 13,452 (341,681) C 3592A3 (encrypted)
|
|
0x74 12.7 (0.5) 2560 19,686 (500,024) C 3592A4 (encrypted)
|
|
0x75 12.7 (0.5) 5120 20,670 (525,018) C 3592A5 (encrypted)
|
|
0x8c 8.0 (0.315) 1 1,789 (45,434) RLL CS EXB-8500c 5,9
|
|
0x90 8.0 (0.315) 1 1,703 (43,245) RLL CS EXB-8200c 5,9
|
|
.Ed
|
|
.Bd -literal -offset 2n
|
|
Code Description Type Description
|
|
---- -------------------------------------- ---- -----------
|
|
NRZI Non return to zero, change on ones R Reel-to-reel
|
|
GCR Group code recording C Cartridge
|
|
PE Phase encoded CS Cassette
|
|
IMFM Inverted modified frequency modulation
|
|
MFM Modified frequency modulation
|
|
DDS DAT data storage
|
|
RLL Run length limited
|
|
PRML Partial Response Maximum Likelihood
|
|
.Ed
|
|
.Bd -literal -offset 2n
|
|
NOTES
|
|
1. Serial recorded.
|
|
2. Parallel recorded.
|
|
3. Old format known as QIC-11.
|
|
5. Helical scan.
|
|
6. This is not an American National Standard. The reference is based
|
|
on an industry standard definition of the media format.
|
|
7. DLT recording: serially recorded track pairs (DLTapeIII and
|
|
DLTapeIV(20)), or track quads (DLTapeIV(35) and DLTapeIV(40)).
|
|
8. Super DLT (SDLT) recording: 56 serially recorded logical tracks
|
|
with 8 physical tracks each.
|
|
9. Vendor-specific Exabyte density code for compressed format.
|
|
10. bpi/bpmm values for the Oracle/StorageTek T10000 tape drives are
|
|
not listed in the manual. Someone with access to a drive can
|
|
supply the necessary values by running 'mt getdensity'.
|
|
11. This is Exabyte 8200 uncompressed format. The compressed format
|
|
density code is 0x90.
|
|
12. This is Exabyte 8500 uncompressed format. The compressed format
|
|
density code is 0x8c.
|
|
.Ed
|
|
.Sh ENVIRONMENT
|
|
.Bl -tag -width ".Ev TAPE"
|
|
.It Ev TAPE
|
|
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 ".Pa /dev/*sa[0-9]*" -compact
|
|
.It Pa /dev/*sa[0-9]*
|
|
SCSI magnetic tape interface
|
|
.El
|
|
.Sh DIAGNOSTICS
|
|
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 ,
|
|
.Xr mtio 4 ,
|
|
.Xr sa 4 ,
|
|
.Xr environ 7
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
command appeared in
|
|
.Bx 4.3 .
|
|
.Pp
|
|
Extensions regarding the
|
|
.Xr st 4
|
|
driver appeared in
|
|
.Bx 386 0.1
|
|
as a separate
|
|
.Nm st
|
|
command, and have been merged into the
|
|
.Nm
|
|
command in
|
|
.Fx 2.1 .
|
|
.Pp
|
|
The former
|
|
.Cm eof
|
|
command that used to be a synonym for
|
|
.Cm weof
|
|
has been abandoned in
|
|
.Fx 2.1
|
|
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.
|