.\" 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. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 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 .\" .Dd June 6, 1993 .Dt MT 1 .Os BSD 4 .Sh NAME .Nm mt .Nd magnetic tape manipulating program .Sh SYNOPSIS .Nm .Op Fl f Ar tapename .Ar command .Op Ar count .Sh DESCRIPTION .Nm Mt 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 . Note that .Ar tapename must reference a raw (not block) tape device. .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" .It Cm weof Write .Ar count end-of-file marks at the current position on the tape. .It Cm fsf Forward space .Ar count files. .It Cm fsr Forward space .Ar count records. .It Cm bsf Back space .Ar count files. .It Cm bsr Back space .Ar count records. .It Cm rewind Rewind the tape (Count is ignored). .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. .It Cm retension Re-tension the tape (one full wind forth and back, Count is ignored). .It Cm status Print status information about the tape unit. .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 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: .Pp .Bl -tag -width 123456789 -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 tape 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. .El .Pp If a tape name is not specified, and the environment variable .Ev TAPE does not exist; .Nm uses the device .Pa /dev/nrsa0 . .Pp .Nm Mt 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 .Bd -literal -offset 3n 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 0x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 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 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 .Ed .Bd -literal -offset 3n 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 .Ed .Bd -literal -offset 3n 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. .Ed .Sh ENVIRONMENT If the following environment variable exists, it is utilized by .Nm mt . .Bl -tag -width Fl .It Ev TAPE .Nm Mt checks the .Ev TAPE environment variable if the argument .Ar tapename is not given. .Sh FILES .Bl -tag -width /dev/*rst[0-9]*xx -compact .It Pa /dev/*rwt* QIC-02/QIC-36 magnetic tape interface .It Pa /dev/*rsa[0-9]* SCSI magnetic tape interface .El .Sh SEE ALSO .Xr dd 1 , .Xr ioctl 2 , .Xr mtio 4 , .Xr st 4 , .Xr wt 4 , .Xr environ 7 .Sh HISTORY The .Nm command appeared in .Bx 4.3 . .Pp Extensions regarding the .Xr st 4 driver appeared in 386BSD 0.1 as a separate .Xr st 1 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.