1.\" Copyright (c) 1981, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. All advertising materials mentioning features or use of this software 14.\" must display the following acknowledgement: 15.\" This product includes software developed by the University of 16.\" California, Berkeley and its contributors. 17.\" 4. Neither the name of the University nor the names of its contributors 18.\" may be used to endorse or promote products derived from this software 19.\" without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.\" @(#)mt.1 8.1 (Berkeley) 6/6/93 34.\" $FreeBSD$ 35.\" 36.Dd June 6, 1993 37.Dt MT 1 38.Os BSD 4 39.Sh NAME 40.Nm mt 41.Nd magnetic tape manipulating program 42.Sh SYNOPSIS 43.Nm 44.Op Fl f Ar tapename 45.Ar command 46.Op Ar count 47.Sh DESCRIPTION 48.Nm Mt 49is used to give commands to a magnetic tape drive. 50By default 51.Nm 52performs the requested operation once. Operations 53may be performed multiple times by specifying 54.Ar count . 55Note 56that 57.Ar tapename 58must reference a raw (not block) tape device. 59.Pp 60The available commands are listed below. Only as many 61characters as are required to uniquely identify a command 62need be specified. 63.Bl -tag -width "eof, weof" 64.It Cm weof 65Write 66.Ar count 67end-of-file marks at the current position on the tape. 68.It Cm smk 69Write 70.Ar count 71setmarks at the current position on the tape. 72.It Cm fsf 73Forward space 74.Ar count 75files. 76.It Cm fsr 77Forward space 78.Ar count 79records. 80.It Cm fss 81Forward space 82.Ar count 83setmarks. 84.It Cm bsf 85Backward space 86.Ar count 87files. 88.It Cm bsr 89Backward space 90.Ar count 91records. 92.It Cm bss 93Backward space 94.Ar count 95setmarks. 96.It Cm rdhpos 97Read Hardware block position. Some drives do not support this. The block 98number reported is specific for that hardware only. The count argument is 99ignored. 100.It Cm rdspos 101Read SCSI logical block position. Some drives do not support this. The 102count argument is ignored. 103.It Cm sethpos 104Set Hardware block position. Some drives do not support this. The count 105argument is interpreted as a hardware block to which to position the tape. 106.It Cm setspos 107Set SCSI logical block position. Some drives do not support this. The count 108argument is interpreted as a SCSI logical block to which to position the tape. 109.It Cm rewind 110Rewind the tape 111(Count is ignored). 112.It Cm offline , rewoffl 113Rewind the tape and place the tape unit off-line 114(Count is ignored). 115.It Cm erase 116Erase the tape. 117A count of 0 disables long erase, which is on by default. 118.It Cm retension 119Re-tension the tape 120(one full wind forth and back, Count is ignored). 121.It Cm status 122Print status information about the tape unit. For SCSI magnetic tape devices, 123the current operating modes of density, blocksize, and whether compression 124is enabled is reported. The current state of the driver (what it thinks that 125it is doing with the device) is reported. If the driver knows the relative 126position from BOT (in terms of filemarks and records), it prints that. Note 127that this information is not definitive (only BOT, End of Recorded Media, and 128hardware or SCSI logical block position (if the drive supports such) are 129considered definitive tape positions). 130.It Cm errstat 131Print (and clear) error status information about this device. For every normal 132operation (e.g., a read or a write) and every control operation (e.g,, a 133rewind), the driver stores up the last command executed and it's associated 134status and any residual counts (if any). This command retrieves and prints this 135information. If possible, this also clears any latched error information. 136.It Cm blocksize 137Set the block size for the tape unit. Zero means variable-length 138blocks. 139.It Cm density 140Set the density for the tape unit. For the density codes, see below. 141The density value could be given either numerically, or as a string, 142corresponding to the 143.Dq Reference 144field. If the string is abbreviated, it will be resolved in the order 145shown in the table, and the first matching entry will be used. If the 146given string and the resulting canonical density name do not match 147exactly, an informational message is printed about what the given 148string has been taken for. 149.It Cm geteotmodel 150Fetch and print out the current EOT filemark model. The model states how 151many filemarks will be written at close if a tape was being written. 152.It Cm seteotmodel 153Set (from the 154.Ar count 155argument) 156and print out the current and EOT filemark model. Typically this will be 157.Ar 2 158filemarks, but some devices (typically QIC cartridge drives) can 159only write 160.Ar 1 161filemark. Currently you can only choose a value of 162.Ar 1 163or 164.Ar 2 . 165.It Cm eom 166Forward space to end of recorded medium 167(Count is ignored). 168.It Cm eod 169Forward space to end of data, identical to 170.Cm eom . 171.It Cm comp 172Set compression mode. 173There are currently several possible values for the compression mode: 174.Pp 175.Bl -tag -width 123456789 -compact 176.It off 177Turn compression off 178.It on 179Turn compression on 180.It none 181Same as 182.Ar off 183.It enable 184Same as 185.Ar on 186.It IDRC 187IBM Improved Data Recording Capability compression (0x10). 188.It DCLZ 189DCLZ compression algorithm (0x20). 190.El 191.Pp 192In addition to the above recognized compression keywords, the user can 193supply a numeric compression algorithm for the tape drive to use. In most 194cases, simply turning the compression 195.Sq on 196will have the desired effect of enabling the default compression algorithm 197supported by the drive. If this is not the case (see the 198.Cm status 199display to see which compression algorithm is currently in use), the user 200can manually specify one of the supported compression keywords (above), or 201supply a numeric compression value. 202.El 203.Pp 204If a tape name is not specified, and the environment variable 205.Ev TAPE 206does not exist; 207.Nm 208uses the device 209.Pa /dev/nrsa0 . 210.Pp 211.Nm Mt 212returns a 0 exit status when the operation(s) were successful, 2131 if the command was unrecognized, and 2 if an operation failed. 214.Pp 215The following density table was taken from the 216.Sq Historical sequential access density codes 217table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC) 218working draft, dated November 11, 1997. 219.Pp 220The different density codes are as follows: 221.Pp 222.Dl 0x0 default for device 223.Dl 0xE reserved for ECMA 224.Bd -literal -offset 3n 225Value Width Tracks Density Code Type Reference Note 226 mm in bpmm bpi 2270x01 12.7 (0.5) 9 32 (800) NRZI R X3.22-1983 2 2280x02 12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2 2290x03 12.7 (0.5) 9 246 (6,250) GCR R X3.54-1986 2 2300x05 6.3 (0.25) 4/9 315 (8,000) GCR C X3.136-1986 1 2310x06 12.7 (0.5) 9 126 (3,200) PE R X3.157-1987 2 2320x07 6.3 (0.25) 4 252 (6,400) IMFM C X3.116-1986 1 2330x08 3.81 (0.15) 4 315 (8,000) GCR CS X3.158-1987 1 2340x09 12.7 (0.5) 18 1,491 (37,871) GCR C X3.180 2 2350x0A 12.7 (0.5) 22 262 (6,667) MFM C X3B5/86-199 1 2360x0B 6.3 (0.25) 4 63 (1,600) PE C X3.56-1986 1 2370x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1 1,6 2380x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2 1,6 2390x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120 1,6 2400x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150 1,6 2410x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320 1,6 2420x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350 1,6 2430x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A 5 2440x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5 2450x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 2460x16 12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1 2470x17 12.7 (0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1 2480x18 12.7 (0.5) 112 1,673 (42,500) MFM C X3B5/92-50 1 2490x1C 6.3 (0.25) 34 1,654 (42,000) MFM C QIC-385M 1,6 2500x1D 6.3 (0.25) 32 1,512 (38,400) GCR C QIC-410M 1,6 2510x1E 6.3 (0.25) 30 1,385 (36,000) GCR C QIC-1000C 1,6 2520x1F 6.3 (0.25) 30 2,666 (67,733) RLL C QIC-2100C 1,6 2530x20 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-6GB(M) 1,6 2540x21 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-20GB(C) 1,6 2550x22 6.3 (0.25) 42 1,600 (40,640) GCR C QIC-2GB(C) ? 2560x23 6.3 (0.25) 38 2,666 (67,733) RLL C QIC-875M ? 2570x24 3.81 (0.15) 1 2,400 (61,000) CS DDS-2 5 2580x25 3.81 (0.15) 1 3,816 (97,000) CS DDS-3 5 2590x26 3.81 (0.15) 1 3,816 (97,000) CS DDS-4 5 2600x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth 5 2610x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224 1 2620x29 12.7 (0.5) 2630x2A 2640x2B 12.7 (0.5) 3 ? ? ? C X3.267 5 265.Ed 266 267.Bd -literal -offset 3n 268Code Description Type Description 269---------------- ---------------- 270NRZI Non return to zero, change on ones R Reel-to-reel 271GCR Group code recording C Cartridge 272PE Phase encoded CS Cassette 273IMFM Inverted modified frequency modulation 274MFM Modified frequency modulation 275DDS DAT data storage 276RLL Run length limited 277.Ed 278 279.Bd -literal -offset 3n 280NOTES 2811. Serial recorded. 2822. Parallel recorded. 2833. Old format known as QIC-11. 2845. Helical scan. 2856. This is not an American National Standard. The reference is based on 286 an industry standard definition of the media format. 287.Ed 288 289.Sh ENVIRONMENT 290If the following environment variable exists, it is utilized by 291.Nm mt . 292.Bl -tag -width Fl 293.It Ev TAPE 294.Nm Mt 295checks the 296.Ev TAPE 297environment variable if the 298argument 299.Ar tapename 300is not given. 301.Sh FILES 302.Bl -tag -width /dev/*rst[0-9]*xx -compact 303.It Pa /dev/*rwt* 304QIC-02/QIC-36 magnetic tape interface 305.It Pa /dev/*rsa[0-9]* 306SCSI magnetic tape interface 307.El 308.Sh SEE ALSO 309.Xr dd 1 , 310.Xr ioctl 2 , 311.Xr mtio 4 , 312.Xr sa 4 , 313.Xr wt 4 , 314.Xr environ 7 315.Sh HISTORY 316The 317.Nm 318command appeared in 319.Bx 4.3 . 320.Pp 321Extensions regarding the 322.Xr st 4 323driver appeared in 386BSD 0.1 as a separate 324.Xr st 1 325command, and have been merged into the 326.Nm 327command in 328.Fx 2.1 . 329.Pp 330The former 331.Cm eof 332command that used to be a synonym for 333.Cm weof 334has been abandoned in 335.Fx 2.1 336since it was often confused with 337.Cm eom , 338which is fairly dangerous. 339