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. Neither the name of the University nor the names of its contributors 14.\" may be used to endorse or promote products derived from this software 15.\" without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.\" @(#)mt.1 8.1 (Berkeley) 6/6/93 30.\" $FreeBSD: src/usr.bin/mt/mt.1,v 1.19.2.8 2002/11/08 11:35:57 joerg Exp $ 31.\" 32.Dd June 6, 1993 33.Dt MT 1 34.Os 35.Sh NAME 36.Nm mt 37.Nd magnetic tape manipulating program 38.Sh SYNOPSIS 39.Nm 40.Op Fl f Ar tapename 41.Ar command 42.Op Ar count 43.Sh DESCRIPTION 44The 45.Nm 46utility is used to give commands to a magnetic tape drive. 47By default 48.Nm 49performs the requested operation once. Operations 50may be performed multiple times by specifying 51.Ar count . 52Note 53that 54.Ar tapename 55must reference a raw (not block) tape device. 56.Pp 57The available commands are listed below. Only as many 58characters as are required to uniquely identify a command 59need be specified. 60.Bl -tag -width "eof, weof" 61.It Cm weof 62Write 63.Ar count 64end-of-file marks at the current position on the tape. 65.It Cm smk 66Write 67.Ar count 68setmarks at the current position on the tape. 69.It Cm fsf 70Forward space 71.Ar count 72files. 73.It Cm fsr 74Forward space 75.Ar count 76records. 77.It Cm fss 78Forward space 79.Ar count 80setmarks. 81.It Cm bsf 82Backward space 83.Ar count 84files. 85.It Cm bsr 86Backward space 87.Ar count 88records. 89.It Cm bss 90Backward space 91.Ar count 92setmarks. 93.It Cm rdhpos 94Read Hardware block position. 95Some drives do not support this. 96The block 97number reported is specific for that hardware only. 98The count argument is 99ignored. 100.It Cm rdspos 101Read SCSI logical block position. 102Some drives do not support this. 103The 104count argument is ignored. 105.It Cm sethpos 106Set Hardware block position. 107Some drives do not support this. 108The count 109argument is interpreted as a hardware block to which to position the tape. 110.It Cm setspos 111Set SCSI logical block position. 112Some drives do not support this. 113The count 114argument is interpreted as a SCSI logical block to which to position the tape. 115.It Cm rewind 116Rewind the tape 117(Count is ignored). 118.It Cm offline , rewoffl 119Rewind the tape and place the tape unit off-line 120(Count is ignored). 121.It Cm erase 122Erase the tape. 123A count of 0 disables long erase, which is on by default. 124.It Cm retension 125Re-tension the tape 126(one full wind forth and back, Count is ignored). 127.It Cm status 128Print status information about the tape unit. 129For SCSI magnetic tape devices, 130the current operating modes of density, blocksize, and whether compression 131is enabled is reported. 132The current state of the driver (what it thinks that 133it is doing with the device) is reported. 134If the driver knows the relative 135position from BOT (in terms of filemarks and records), it prints that. 136Note 137that this information is not definitive (only BOT, End of Recorded Media, and 138hardware or SCSI logical block position (if the drive supports such) are 139considered definitive tape positions). 140.It Cm errstat 141Print (and clear) error status information about this device. 142For every normal 143operation (e.g., a read or a write) and every control operation (e.g,, a 144rewind), the driver stores up the last command executed and it's associated 145status and any residual counts (if any). This command retrieves and prints this 146information. 147If possible, this also clears any latched error information. 148.It Cm blocksize 149Set the block size for the tape unit. Zero means variable-length 150blocks. 151.It Cm density 152Set the density for the tape unit. For the density codes, see below. 153The density value could be given either numerically, or as a string, 154corresponding to the 155.Dq Reference 156field. If the string is abbreviated, it will be resolved in the order 157shown in the table, and the first matching entry will be used. If the 158given string and the resulting canonical density name do not match 159exactly, an informational message is printed about what the given 160string has been taken for. 161.It Cm geteotmodel 162Fetch and print out the current EOT filemark model. 163The model states how 164many filemarks will be written at close if a tape was being written. 165.It Cm seteotmodel 166Set (from the 167.Ar count 168argument) 169and print out the current and EOT filemark model. 170Typically this will be 171.Ar 2 172filemarks, but some devices (typically QIC cartridge drives) can 173only write 174.Ar 1 175filemark. 176Currently you can only choose a value of 177.Ar 1 178or 179.Ar 2 . 180.It Cm eom 181Forward space to end of recorded medium 182(Count is ignored). 183.It Cm eod 184Forward space to end of data, identical to 185.Cm eom . 186.It Cm comp 187Set compression mode. 188There are currently several possible values for the compression mode: 189.Pp 190.Bl -tag -width 9n -compact 191.It off 192Turn compression off. 193.It on 194Turn compression on. 195.It none 196Same as 197.Ar off . 198.It enable 199Same as 200.Ar on . 201.It IDRC 202IBM Improved Data Recording Capability compression (0x10). 203.It DCLZ 204DCLZ compression algorithm (0x20). 205.El 206.Pp 207In addition to the above recognized compression keywords, the user can 208supply a numeric compression algorithm for the tape drive to use. In most 209cases, simply turning the compression 210.Sq on 211will have the desired effect of enabling the default compression algorithm 212supported by the drive. If this is not the case (see the 213.Cm status 214display to see which compression algorithm is currently in use), the user 215can manually specify one of the supported compression keywords (above), or 216supply a numeric compression value. 217.El 218.Pp 219If a tape name is not specified, and the environment variable 220.Ev TAPE 221does not exist; 222.Nm 223uses the device 224.Pa /dev/nsa0 . 225.Pp 226The 227.Nm 228utility returns a 0 exit status when the operation(s) were successful, 2291 if the command was unrecognized, and 2 if an operation failed. 230.Pp 231The following density table was taken from the 232.Sq Historical sequential access density codes 233table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC) 234working draft, dated November 11, 1997. 235.Pp 236The different density codes are as follows: 237.Pp 238.Dl "0x0 default for device" 239.Dl "0xE reserved for ECMA" 240.Bd -literal -offset 3n 241Value Width Tracks Density Code Type Reference Note 242 mm in bpmm bpi 2430x01 12.7 (0.5) 9 32 (800) NRZI R X3.22-1983 2 2440x02 12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2 2450x03 12.7 (0.5) 9 246 (6,250) GCR R X3.54-1986 2 2460x05 6.3 (0.25) 4/9 315 (8,000) GCR C X3.136-1986 1 2470x06 12.7 (0.5) 9 126 (3,200) PE R X3.157-1987 2 2480x07 6.3 (0.25) 4 252 (6,400) IMFM C X3.116-1986 1 2490x08 3.81 (0.15) 4 315 (8,000) GCR CS X3.158-1987 1 2500x09 12.7 (0.5) 18 1,491 (37,871) GCR C X3.180 2 2510x0A 12.7 (0.5) 22 262 (6,667) MFM C X3B5/86-199 1 2520x0B 6.3 (0.25) 4 63 (1,600) PE C X3.56-1986 1 2530x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1 1,6 2540x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2 1,6 2550x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120 1,6 2560x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150 1,6 2570x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320 1,6 2580x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350 1,6 2590x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A 5 2600x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5 2610x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 2620x16 12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1 2630x17 12.7 (0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1 2640x18 12.7 (0.5) 112 1,673 (42,500) MFM C X3B5/92-50 1 2650x19 12.7 (0.5) 128 2,460 (62,500) RLL C DLTapeIII 6,7 2660x1A 12.7 (0.5) 128 3,214 (81,633) RLL C DLTapeIV(20) 6,7 2670x1B 12.7 (0.5) 208 3,383 (85,937) RLL C DLTapeIV(35) 6,7 2680x1C 6.3 (0.25) 34 1,654 (42,000) MFM C QIC-385M 1,6 2690x1D 6.3 (0.25) 32 1,512 (38,400) GCR C QIC-410M 1,6 2700x1E 6.3 (0.25) 30 1,385 (36,000) GCR C QIC-1000C 1,6 2710x1F 6.3 (0.25) 30 2,666 (67,733) RLL C QIC-2100C 1,6 2720x20 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-6GB(M) 1,6 2730x21 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-20GB(C) 1,6 2740x22 6.3 (0.25) 42 1,600 (40,640) GCR C QIC-2GB(C) ? 2750x23 6.3 (0.25) 38 2,666 (67,733) RLL C QIC-875M ? 2760x24 3.81 (0.15) 1 2,400 (61,000) CS DDS-2 5 2770x25 3.81 (0.15) 1 3,816 (97,000) CS DDS-3 5 2780x26 3.81 (0.15) 1 3,816 (97,000) CS DDS-4 5 2790x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth 5 2800x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224 1 2810x29 12.7 (0.5) 2820x2A 2830x2B 12.7 (0.5) 3 ? ? ? C X3.267 5 2840x41 12.7 (0.5) 208 3,868 (98,250) RLL C DLTapeIV(40) 6,7 2850x48 12.7 (0.5) 448 5,236 (133,000) PRML C SDLTapeI(110) 6,8 2860x49 12.7 (0.5) 448 7,598 (193,000) PRML C SDLTapeI(160) 6,8 287.Ed 288.Bd -literal -offset 3n 289Code Description Type Description 290---------------- ---------------- 291NRZI Non return to zero, change on ones R Reel-to-reel 292GCR Group code recording C Cartridge 293PE Phase encoded CS Cassette 294IMFM Inverted modified frequency modulation 295MFM Modified frequency modulation 296DDS DAT data storage 297RLL Run length limited 298PRML Partial Response Maximum Likelihood 299.Ed 300.Bd -literal -offset 3n 301NOTES 3021. Serial recorded. 3032. Parallel recorded. 3043. Old format known as QIC-11. 3055. Helical scan. 3066. This is not an American National Standard. The reference is based on 307 an industry standard definition of the media format. 3087. DLT recording: serially recorded track pairs (DLTapeIII and 309 DLTapeIV(20)), or track quads (DLTapeIV(35) and DLTapeIV(40)). 3108. Super DLT (SDLT) recording: 56 serially recorded logical tracks with 311 8 physical tracks each. 312.Ed 313.Sh ENVIRONMENT 314If the following environment variable exists, it is utilized by 315.Nm . 316.Bl -tag -width Fl 317.It Ev TAPE 318The 319.Nm 320utility checks the 321.Ev TAPE 322environment variable if the 323argument 324.Ar tapename 325is not given. 326.El 327.Sh FILES 328.Bl -tag -width /dev/*rst[0-9]*xx -compact 329.It Pa /dev/*rsa[0-9]* 330SCSI magnetic tape interface 331.El 332.Sh SEE ALSO 333.Xr dd 1 , 334.Xr ioctl 2 , 335.Xr mtio 4 , 336.Xr sa 4 , 337.Xr environ 7 338.Sh HISTORY 339The 340.Nm 341command appeared in 342.Bx 4.3 . 343.Pp 344Extensions regarding the 345.Xr st 4 346driver appeared in 347.Bx 386 0.1 348as a separate 349.Xr st 1 350command, and have been merged into the 351.Nm 352command in 353.Fx 2.1 . 354.Pp 355The former 356.Cm eof 357command that used to be a synonym for 358.Cm weof 359has been abandoned in 360.Fx 2.1 361since it was often confused with 362.Cm eom , 363which is fairly dangerous. 364