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: src/usr.bin/mt/mt.1,v 1.19.2.8 2002/11/08 11:35:57 joerg Exp $ 35.\" $DragonFly: src/usr.bin/mt/mt.1,v 1.2 2003/06/17 04:29:29 dillon Exp $ 36.\" 37.Dd June 6, 1993 38.Dt MT 1 39.Os 40.Sh NAME 41.Nm mt 42.Nd magnetic tape manipulating program 43.Sh SYNOPSIS 44.Nm 45.Op Fl f Ar tapename 46.Ar command 47.Op Ar count 48.Sh DESCRIPTION 49The 50.Nm 51utility is used to give commands to a magnetic tape drive. 52By default 53.Nm 54performs the requested operation once. Operations 55may be performed multiple times by specifying 56.Ar count . 57Note 58that 59.Ar tapename 60must reference a raw (not block) tape device. 61.Pp 62The available commands are listed below. Only as many 63characters as are required to uniquely identify a command 64need be specified. 65.Bl -tag -width "eof, weof" 66.It Cm weof 67Write 68.Ar count 69end-of-file marks at the current position on the tape. 70.It Cm smk 71Write 72.Ar count 73setmarks at the current position on the tape. 74.It Cm fsf 75Forward space 76.Ar count 77files. 78.It Cm fsr 79Forward space 80.Ar count 81records. 82.It Cm fss 83Forward space 84.Ar count 85setmarks. 86.It Cm bsf 87Backward space 88.Ar count 89files. 90.It Cm bsr 91Backward space 92.Ar count 93records. 94.It Cm bss 95Backward space 96.Ar count 97setmarks. 98.It Cm rdhpos 99Read Hardware block position. 100Some drives do not support this. 101The block 102number reported is specific for that hardware only. 103The count argument is 104ignored. 105.It Cm rdspos 106Read SCSI logical block position. 107Some drives do not support this. 108The 109count argument is ignored. 110.It Cm sethpos 111Set Hardware block position. 112Some drives do not support this. 113The count 114argument is interpreted as a hardware block to which to position the tape. 115.It Cm setspos 116Set SCSI logical block position. 117Some drives do not support this. 118The count 119argument is interpreted as a SCSI logical block to which to position the tape. 120.It Cm rewind 121Rewind the tape 122(Count is ignored). 123.It Cm offline , rewoffl 124Rewind the tape and place the tape unit off-line 125(Count is ignored). 126.It Cm erase 127Erase the tape. 128A count of 0 disables long erase, which is on by default. 129.It Cm retension 130Re-tension the tape 131(one full wind forth and back, Count is ignored). 132.It Cm status 133Print status information about the tape unit. 134For SCSI magnetic tape devices, 135the current operating modes of density, blocksize, and whether compression 136is enabled is reported. 137The current state of the driver (what it thinks that 138it is doing with the device) is reported. 139If the driver knows the relative 140position from BOT (in terms of filemarks and records), it prints that. 141Note 142that this information is not definitive (only BOT, End of Recorded Media, and 143hardware or SCSI logical block position (if the drive supports such) are 144considered definitive tape positions). 145.It Cm errstat 146Print (and clear) error status information about this device. 147For every normal 148operation (e.g., a read or a write) and every control operation (e.g,, a 149rewind), the driver stores up the last command executed and it's associated 150status and any residual counts (if any). This command retrieves and prints this 151information. 152If possible, this also clears any latched error information. 153.It Cm blocksize 154Set the block size for the tape unit. Zero means variable-length 155blocks. 156.It Cm density 157Set the density for the tape unit. For the density codes, see below. 158The density value could be given either numerically, or as a string, 159corresponding to the 160.Dq Reference 161field. If the string is abbreviated, it will be resolved in the order 162shown in the table, and the first matching entry will be used. If the 163given string and the resulting canonical density name do not match 164exactly, an informational message is printed about what the given 165string has been taken for. 166.It Cm geteotmodel 167Fetch and print out the current EOT filemark model. 168The model states how 169many filemarks will be written at close if a tape was being written. 170.It Cm seteotmodel 171Set (from the 172.Ar count 173argument) 174and print out the current and EOT filemark model. 175Typically this will be 176.Ar 2 177filemarks, but some devices (typically QIC cartridge drives) can 178only write 179.Ar 1 180filemark. 181Currently you can only choose a value of 182.Ar 1 183or 184.Ar 2 . 185.It Cm eom 186Forward space to end of recorded medium 187(Count is ignored). 188.It Cm eod 189Forward space to end of data, identical to 190.Cm eom . 191.It Cm comp 192Set compression mode. 193There are currently several possible values for the compression mode: 194.Pp 195.Bl -tag -width 9n -compact 196.It off 197Turn compression off. 198.It on 199Turn compression on. 200.It none 201Same as 202.Ar off . 203.It enable 204Same as 205.Ar on . 206.It IDRC 207IBM Improved Data Recording Capability compression (0x10). 208.It DCLZ 209DCLZ compression algorithm (0x20). 210.El 211.Pp 212In addition to the above recognized compression keywords, the user can 213supply a numeric compression algorithm for the tape drive to use. In most 214cases, simply turning the compression 215.Sq on 216will have the desired effect of enabling the default compression algorithm 217supported by the drive. If this is not the case (see the 218.Cm status 219display to see which compression algorithm is currently in use), the user 220can manually specify one of the supported compression keywords (above), or 221supply a numeric compression value. 222.El 223.Pp 224If a tape name is not specified, and the environment variable 225.Ev TAPE 226does not exist; 227.Nm 228uses the device 229.Pa /dev/nsa0 . 230.Pp 231The 232.Nm 233utility returns a 0 exit status when the operation(s) were successful, 2341 if the command was unrecognized, and 2 if an operation failed. 235.Pp 236The following density table was taken from the 237.Sq Historical sequential access density codes 238table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC) 239working draft, dated November 11, 1997. 240.Pp 241The different density codes are as follows: 242.Pp 243.Dl "0x0 default for device" 244.Dl "0xE reserved for ECMA" 245.Bd -literal -offset 3n 246Value Width Tracks Density Code Type Reference Note 247 mm in bpmm bpi 2480x01 12.7 (0.5) 9 32 (800) NRZI R X3.22-1983 2 2490x02 12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2 2500x03 12.7 (0.5) 9 246 (6,250) GCR R X3.54-1986 2 2510x05 6.3 (0.25) 4/9 315 (8,000) GCR C X3.136-1986 1 2520x06 12.7 (0.5) 9 126 (3,200) PE R X3.157-1987 2 2530x07 6.3 (0.25) 4 252 (6,400) IMFM C X3.116-1986 1 2540x08 3.81 (0.15) 4 315 (8,000) GCR CS X3.158-1987 1 2550x09 12.7 (0.5) 18 1,491 (37,871) GCR C X3.180 2 2560x0A 12.7 (0.5) 22 262 (6,667) MFM C X3B5/86-199 1 2570x0B 6.3 (0.25) 4 63 (1,600) PE C X3.56-1986 1 2580x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1 1,6 2590x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2 1,6 2600x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120 1,6 2610x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150 1,6 2620x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320 1,6 2630x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350 1,6 2640x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A 5 2650x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5 2660x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 2670x16 12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1 2680x17 12.7 (0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1 2690x18 12.7 (0.5) 112 1,673 (42,500) MFM C X3B5/92-50 1 2700x19 12.7 (0.5) 128 2,460 (62,500) RLL C DLTapeIII 6,7 2710x1A 12.7 (0.5) 128 3,214 (81,633) RLL C DLTapeIV(20) 6,7 2720x1B 12.7 (0.5) 208 3,383 (85,937) RLL C DLTapeIV(35) 6,7 2730x1C 6.3 (0.25) 34 1,654 (42,000) MFM C QIC-385M 1,6 2740x1D 6.3 (0.25) 32 1,512 (38,400) GCR C QIC-410M 1,6 2750x1E 6.3 (0.25) 30 1,385 (36,000) GCR C QIC-1000C 1,6 2760x1F 6.3 (0.25) 30 2,666 (67,733) RLL C QIC-2100C 1,6 2770x20 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-6GB(M) 1,6 2780x21 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-20GB(C) 1,6 2790x22 6.3 (0.25) 42 1,600 (40,640) GCR C QIC-2GB(C) ? 2800x23 6.3 (0.25) 38 2,666 (67,733) RLL C QIC-875M ? 2810x24 3.81 (0.15) 1 2,400 (61,000) CS DDS-2 5 2820x25 3.81 (0.15) 1 3,816 (97,000) CS DDS-3 5 2830x26 3.81 (0.15) 1 3,816 (97,000) CS DDS-4 5 2840x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth 5 2850x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224 1 2860x29 12.7 (0.5) 2870x2A 2880x2B 12.7 (0.5) 3 ? ? ? C X3.267 5 2890x41 12.7 (0.5) 208 3,868 (98,250) RLL C DLTapeIV(40) 6,7 2900x48 12.7 (0.5) 448 5,236 (133,000) PRML C SDLTapeI(110) 6,8 2910x49 12.7 (0.5) 448 7,598 (193,000) PRML C SDLTapeI(160) 6,8 292.Ed 293.Bd -literal -offset 3n 294Code Description Type Description 295---------------- ---------------- 296NRZI Non return to zero, change on ones R Reel-to-reel 297GCR Group code recording C Cartridge 298PE Phase encoded CS Cassette 299IMFM Inverted modified frequency modulation 300MFM Modified frequency modulation 301DDS DAT data storage 302RLL Run length limited 303PRML Partial Response Maximum Likelihood 304.Ed 305.Bd -literal -offset 3n 306NOTES 3071. Serial recorded. 3082. Parallel recorded. 3093. Old format known as QIC-11. 3105. Helical scan. 3116. This is not an American National Standard. The reference is based on 312 an industry standard definition of the media format. 3137. DLT recording: serially recorded track pairs (DLTapeIII and 314 DLTapeIV(20)), or track quads (DLTapeIV(35) and DLTapeIV(40)). 3158. Super DLT (SDLT) recording: 56 serially recorded logical tracks with 316 8 physical tracks each. 317.Ed 318.Sh ENVIRONMENT 319If the following environment variable exists, it is utilized by 320.Nm . 321.Bl -tag -width Fl 322.It Ev TAPE 323The 324.Nm 325utility checks the 326.Ev TAPE 327environment variable if the 328argument 329.Ar tapename 330is not given. 331.El 332.Sh FILES 333.Bl -tag -width /dev/*rst[0-9]*xx -compact 334.It Pa /dev/*rwt* 335QIC-02/QIC-36 magnetic tape interface 336.It Pa /dev/*rsa[0-9]* 337SCSI magnetic tape interface 338.El 339.Sh SEE ALSO 340.Xr dd 1 , 341.Xr ioctl 2 , 342.Xr mtio 4 , 343.Xr sa 4 , 344.Xr wt 4 , 345.Xr environ 7 346.Sh HISTORY 347The 348.Nm 349command appeared in 350.Bx 4.3 . 351.Pp 352Extensions regarding the 353.Xr st 4 354driver appeared in 355.Bx 386 0.1 356as a separate 357.Xr st 1 358command, and have been merged into the 359.Nm 360command in 361.Fx 2.1 . 362.Pp 363The former 364.Cm eof 365command that used to be a synonym for 366.Cm weof 367has been abandoned in 368.Fx 2.1 369since it was often confused with 370.Cm eom , 371which is fairly dangerous. 372