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 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 48The 49.Nm 50utility is used to give commands to a magnetic tape drive. 51By default 52.Nm 53performs the requested operation once. 54Operations 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. 63Only as many 64characters as are required to uniquely identify a command 65need be specified. 66.Bl -tag -width "eof, weof" 67.It Cm weof 68Write 69.Ar count 70end-of-file marks at the current position on the tape. 71.It Cm smk 72Write 73.Ar count 74setmarks at the current position on the tape. 75.It Cm fsf 76Forward space 77.Ar count 78files. 79.It Cm fsr 80Forward space 81.Ar count 82records. 83.It Cm fss 84Forward space 85.Ar count 86setmarks. 87.It Cm bsf 88Backward space 89.Ar count 90files. 91.It Cm bsr 92Backward space 93.Ar count 94records. 95.It Cm bss 96Backward space 97.Ar count 98setmarks. 99.It Cm rdhpos 100Read Hardware block position. 101Some drives do not support this. 102The block 103number reported is specific for that hardware only. 104The count argument is 105ignored. 106.It Cm rdspos 107Read SCSI logical block position. 108Some drives do not support this. 109The 110count argument is ignored. 111.It Cm sethpos 112Set Hardware block position. 113Some drives do not support this. 114The count 115argument is interpreted as a hardware block to which to position the tape. 116.It Cm setspos 117Set SCSI logical block position. 118Some drives do not support this. 119The count 120argument is interpreted as a SCSI logical block to which to position the tape. 121.It Cm rewind 122Rewind the tape 123(Count is ignored). 124.It Cm offline , rewoffl 125Rewind the tape and place the tape unit off-line 126(Count is ignored). 127.It Cm erase 128Erase the tape. 129A count of 0 disables long erase, which is on by default. 130.It Cm retension 131Re-tension the tape 132(one full wind forth and back, Count is ignored). 133.It Cm status 134Print status information about the tape unit. 135For SCSI magnetic tape devices, 136the current operating modes of density, blocksize, and whether compression 137is enabled is reported. 138The current state of the driver (what it thinks that 139it is doing with the device) is reported. 140If the driver knows the relative 141position from BOT (in terms of filemarks and records), it prints that. 142Note 143that this information is not definitive (only BOT, End of Recorded Media, and 144hardware or SCSI logical block position (if the drive supports such) are 145considered definitive tape positions). 146.It Cm errstat 147Print (and clear) error status information about this device. 148For every normal 149operation (e.g., a read or a write) and every control operation (e.g,, a 150rewind), the driver stores up the last command executed and it's associated 151status and any residual counts (if any). 152This command retrieves and prints this 153information. 154If possible, this also clears any latched error information. 155.It Cm blocksize 156Set the block size for the tape unit. 157Zero means variable-length 158blocks. 159.It Cm density 160Set the density for the tape unit. 161For the density codes, see below. 162The density value could be given either numerically, or as a string, 163corresponding to the 164.Dq Reference 165field. 166If the string is abbreviated, it will be resolved in the order 167shown in the table, and the first matching entry will be used. 168If the 169given string and the resulting canonical density name do not match 170exactly, an informational message is printed about what the given 171string has been taken for. 172.It Cm geteotmodel 173Fetch and print out the current EOT filemark model. 174The model states how 175many filemarks will be written at close if a tape was being written. 176.It Cm seteotmodel 177Set (from the 178.Ar count 179argument) 180and print out the current and EOT filemark model. 181Typically this will be 182.Ar 2 183filemarks, but some devices (typically QIC cartridge drives) can 184only write 185.Ar 1 186filemark. 187Currently you can only choose a value of 188.Ar 1 189or 190.Ar 2 . 191.It Cm eom 192Forward space to end of recorded medium 193(Count is ignored). 194.It Cm eod 195Forward space to end of data, identical to 196.Cm eom . 197.It Cm comp 198Set compression mode. 199There are currently several possible values for the compression mode: 200.Pp 201.Bl -tag -width 9n -compact 202.It off 203Turn compression off. 204.It on 205Turn compression on. 206.It none 207Same as 208.Ar off . 209.It enable 210Same as 211.Ar on . 212.It IDRC 213IBM Improved Data Recording Capability compression (0x10). 214.It DCLZ 215DCLZ compression algorithm (0x20). 216.El 217.Pp 218In addition to the above recognized compression keywords, the user can 219supply a numeric compression algorithm for the tape drive to use. 220In most 221cases, simply turning the compression 222.Sq on 223will have the desired effect of enabling the default compression algorithm 224supported by the drive. 225If this is not the case (see the 226.Cm status 227display to see which compression algorithm is currently in use), the user 228can manually specify one of the supported compression keywords (above), or 229supply a numeric compression value. 230.El 231.Pp 232If a tape name is not specified, and the environment variable 233.Ev TAPE 234does not exist; 235.Nm 236uses the device 237.Pa /dev/nsa0 . 238.Pp 239The 240.Nm 241utility returns a 0 exit status when the operation(s) were successful, 2421 if the command was unrecognized, and 2 if an operation failed. 243.Pp 244The following density table was taken from the 245.Sq Historical sequential access density codes 246table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC) 247working draft, dated November 11, 1997. 248.Pp 249The different density codes are as follows: 250.Pp 251.Dl "0x0 default for device 252.Dl "0xE reserved for ECMA 253.Bd -literal -offset 3n 254Value Width Tracks Density Code Type Reference Note 255 mm in bpmm bpi 2560x01 12.7 (0.5) 9 32 (800) NRZI R X3.22-1983 2 2570x02 12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2 2580x03 12.7 (0.5) 9 246 (6,250) GCR R X3.54-1986 2 2590x05 6.3 (0.25) 4/9 315 (8,000) GCR C X3.136-1986 1 2600x06 12.7 (0.5) 9 126 (3,200) PE R X3.157-1987 2 2610x07 6.3 (0.25) 4 252 (6,400) IMFM C X3.116-1986 1 2620x08 3.81 (0.15) 4 315 (8,000) GCR CS X3.158-1987 1 2630x09 12.7 (0.5) 18 1,491 (37,871) GCR C X3.180 2 2640x0A 12.7 (0.5) 22 262 (6,667) MFM C X3B5/86-199 1 2650x0B 6.3 (0.25) 4 63 (1,600) PE C X3.56-1986 1 2660x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1 1,6 2670x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2 1,6 2680x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120 1,6 2690x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150 1,6 2700x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320 1,6 2710x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350 1,6 2720x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A 5 2730x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5 2740x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 2750x16 12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1 2760x17 12.7 (0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1 2770x18 12.7 (0.5) 112 1,673 (42,500) MFM C X3B5/92-50 1 2780x19 12.7 (0.5) 128 2,460 (62,500) RLL C DLTapeIII 6,7 2790x1A 12.7 (0.5) 128 3,214 (81,633) RLL C DLTapeIV(20) 6,7 2800x1B 12.7 (0.5) 208 3,383 (85,937) RLL C DLTapeIV(35) 6,7 2810x1C 6.3 (0.25) 34 1,654 (42,000) MFM C QIC-385M 1,6 2820x1D 6.3 (0.25) 32 1,512 (38,400) GCR C QIC-410M 1,6 2830x1E 6.3 (0.25) 30 1,385 (36,000) GCR C QIC-1000C 1,6 2840x1F 6.3 (0.25) 30 2,666 (67,733) RLL C QIC-2100C 1,6 2850x20 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-6GB(M) 1,6 2860x21 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-20GB(C) 1,6 2870x22 6.3 (0.25) 42 1,600 (40,640) GCR C QIC-2GB(C) ? 2880x23 6.3 (0.25) 38 2,666 (67,733) RLL C QIC-875M ? 2890x24 3.81 (0.15) 1 2,400 (61,000) CS DDS-2 5 2900x25 3.81 (0.15) 1 3,816 (97,000) CS DDS-3 5 2910x26 3.81 (0.15) 1 3,816 (97,000) CS DDS-4 5 2920x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth 5 2930x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224 1 2940x29 12.7 (0.5) 2950x2A 2960x2B 12.7 (0.5) 3 ? ? ? C X3.267 5 2970x41 12.7 (0.5) 208 3,868 (98,250) RLL C DLTapeIV(40) 6,7 2980x48 12.7 (0.5) 448 5,236 (133,000) PRML C SDLTapeI(110) 6,8 2990x49 12.7 (0.5) 448 7,598 (193,000) PRML C SDLTapeI(160) 6,8 300.Ed 301.Bd -literal -offset 3n 302Code Description Type Description 303---------------- ---------------- 304NRZI Non return to zero, change on ones R Reel-to-reel 305GCR Group code recording C Cartridge 306PE Phase encoded CS Cassette 307IMFM Inverted modified frequency modulation 308MFM Modified frequency modulation 309DDS DAT data storage 310RLL Run length limited 311PRML Partial Response Maximum Likelihood 312.Ed 313.Bd -literal -offset 3n 314NOTES 3151. Serial recorded. 3162. Parallel recorded. 3173. Old format known as QIC-11. 3185. Helical scan. 3196. This is not an American National Standard. The reference is based on 320 an industry standard definition of the media format. 3217. DLT recording: serially recorded track pairs (DLTapeIII and 322 DLTapeIV(20)), or track quads (DLTapeIV(35) and DLTapeIV(40)). 3238. Super DLT (SDLT) recording: 56 serially recorded logical tracks with 324 8 physical tracks each. 325.Ed 326.Sh ENVIRONMENT 327If the following environment variable exists, it is utilized by 328.Nm . 329.Bl -tag -width Fl 330.It Ev TAPE 331The 332.Nm 333utility checks the 334.Ev TAPE 335environment variable if the 336argument 337.Ar tapename 338is not given. 339.El 340.Sh FILES 341.Bl -tag -width /dev/*sa[0-9]*xx -compact 342.It Pa /dev/*wt* 343QIC-02/QIC-36 magnetic tape interface 344.It Pa /dev/*sa[0-9]* 345SCSI magnetic tape interface 346.El 347.Sh SEE ALSO 348.Xr dd 1 , 349.Xr ioctl 2 , 350.Xr ast 4 , 351.Xr mtio 4 , 352.Xr sa 4 , 353.Xr environ 7 354.Sh HISTORY 355The 356.Nm 357command appeared in 358.Bx 4.3 . 359.Pp 360Extensions regarding the 361.Xr st 4 362driver appeared in 363.Bx 386 0.1 364as a separate 365.Nm st 366command, and have been merged into the 367.Nm 368command in 369.Fx 2.1 . 370.Pp 371The former 372.Cm eof 373command that used to be a synonym for 374.Cm weof 375has been abandoned in 376.Fx 2.1 377since it was often confused with 378.Cm eom , 379which is fairly dangerous. 380