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 . 57.Pp 58The available commands are listed below. 59Only as many 60characters as are required to uniquely identify a command 61need be specified. 62.Bl -tag -width "eof, weof" 63.It Cm weof 64Write 65.Ar count 66end-of-file marks at the current position on the tape. 67.It Cm smk 68Write 69.Ar count 70setmarks at the current position on the tape. 71.It Cm fsf 72Forward space 73.Ar count 74files. 75.It Cm fsr 76Forward space 77.Ar count 78records. 79.It Cm fss 80Forward space 81.Ar count 82setmarks. 83.It Cm bsf 84Backward space 85.Ar count 86files. 87.It Cm bsr 88Backward space 89.Ar count 90records. 91.It Cm bss 92Backward space 93.Ar count 94setmarks. 95.It Cm rdhpos 96Read Hardware block position. 97Some drives do not support this. 98The block 99number reported is specific for that hardware only. 100The count argument is 101ignored. 102.It Cm rdspos 103Read SCSI logical block position. 104Some drives do not support this. 105The 106count argument is ignored. 107.It Cm sethpos 108Set Hardware block position. 109Some drives do not support this. 110The count 111argument is interpreted as a hardware block to which to position the tape. 112.It Cm setspos 113Set SCSI logical block position. 114Some drives do not support this. 115The count 116argument is interpreted as a SCSI logical block to which to position the tape. 117.It Cm rewind 118Rewind the tape 119(Count is ignored). 120.It Cm offline , rewoffl 121Rewind the tape and place the tape unit off-line 122(Count is ignored). 123.It Cm erase 124Erase the tape. 125A count of 0 disables long erase, which is on by default. 126.It Cm retension 127Re-tension the tape 128(one full wind forth and back, Count is ignored). 129.It Cm status 130Print status information about the tape unit. 131For SCSI magnetic tape devices, 132the current operating modes of density, blocksize, and whether compression 133is enabled is reported. 134The current state of the driver (what it thinks that 135it is doing with the device) is reported. 136If the driver knows the relative 137position from BOT (in terms of filemarks and records), it prints that. 138Note 139that this information is not definitive (only BOT, End of Recorded Media, and 140hardware or SCSI logical block position (if the drive supports such) are 141considered definitive tape positions). 142.It Cm errstat 143Print (and clear) error status information about this device. 144For every normal 145operation (e.g., a read or a write) and every control operation (e.g,, a 146rewind), the driver stores up the last command executed and it is associated 147status and any residual counts (if any). 148This command retrieves and prints this 149information. 150If possible, this also clears any latched error information. 151.It Cm blocksize 152Set the block size for the tape unit. 153Zero means variable-length 154blocks. 155.It Cm density 156Set the density for the tape unit. 157For the density codes, see below. 158The density value could be given either numerically, or as a string, 159corresponding to the 160.Dq Reference 161field. 162If the string is abbreviated, it will be resolved in the order 163shown in the table, and the first matching entry will be used. 164If the 165given string and the resulting canonical density name do not match 166exactly, an informational message is printed about what the given 167string has been taken for. 168.It Cm geteotmodel 169Fetch and print out the current EOT filemark model. 170The model states how 171many filemarks will be written at close if a tape was being written. 172.It Cm seteotmodel 173Set (from the 174.Ar count 175argument) 176and print out the current and EOT filemark model. 177Typically this will be 178.Ar 2 179filemarks, but some devices (typically QIC cartridge drives) can 180only write 181.Ar 1 182filemark. 183Currently you can only choose a value of 184.Ar 1 185or 186.Ar 2 . 187.It Cm eom 188Forward space to end of recorded medium 189(Count is ignored). 190.It Cm eod 191Forward space to end of data, identical to 192.Cm eom . 193.It Cm comp 194Set compression mode. 195There are currently several possible values for the compression mode: 196.Pp 197.Bl -tag -width 9n -compact 198.It off 199Turn compression off. 200.It on 201Turn compression on. 202.It none 203Same as 204.Ar off . 205.It enable 206Same as 207.Ar on . 208.It IDRC 209IBM Improved Data Recording Capability compression (0x10). 210.It DCLZ 211DCLZ compression algorithm (0x20). 212.El 213.Pp 214In addition to the above recognized compression keywords, the user can 215supply a numeric compression algorithm for the tape drive to use. 216In most 217cases, simply turning the compression 218.Sq on 219will have the desired effect of enabling the default compression algorithm 220supported by the drive. 221If this is not the case (see the 222.Cm status 223display to see which compression algorithm is currently in use), the user 224can manually specify one of the supported compression keywords (above), or 225supply a numeric compression value. 226.El 227.Pp 228If a tape name is not specified, and the environment variable 229.Ev TAPE 230does not exist; 231.Nm 232uses the device 233.Pa /dev/nsa0 . 234.Pp 235The 236.Nm 237utility returns a 0 exit status when the operation(s) were successful, 2381 if the command was unrecognized, and 2 if an operation failed. 239.Pp 240The following density table was taken from the 241.Sq Historical sequential access density codes 242table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC) 243working draft, dated November 11, 1997. 244.Pp 245The different density codes are as follows: 246.Pp 247.Dl "0x0 default for device 248.Dl "0xE reserved for ECMA 249.Bd -literal -offset 3n 250Value Width Tracks Density Code Type Reference Note 251 mm in bpmm bpi 2520x01 12.7 (0.5) 9 32 (800) NRZI R X3.22-1983 2 2530x02 12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2 2540x03 12.7 (0.5) 9 246 (6,250) GCR R X3.54-1986 2 2550x05 6.3 (0.25) 4/9 315 (8,000) GCR C X3.136-1986 1 2560x06 12.7 (0.5) 9 126 (3,200) PE R X3.157-1987 2 2570x07 6.3 (0.25) 4 252 (6,400) IMFM C X3.116-1986 1 2580x08 3.81 (0.15) 4 315 (8,000) GCR CS X3.158-1987 1 2590x09 12.7 (0.5) 18 1,491 (37,871) GCR C X3.180 2 2600x0A 12.7 (0.5) 22 262 (6,667) MFM C X3B5/86-199 1 2610x0B 6.3 (0.25) 4 63 (1,600) PE C X3.56-1986 1 2620x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1 1,6 2630x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2 1,6 2640x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120 1,6 2650x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150 1,6 2660x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320 1,6 2670x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350 1,6 2680x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A 5 2690x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5 2700x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 2710x16 12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1 2720x17 12.7 (0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1 2730x18 12.7 (0.5) 112 1,673 (42,500) MFM C X3B5/92-50 1 2740x19 12.7 (0.5) 128 2,460 (62,500) RLL C DLTapeIII 6,7 2750x1A 12.7 (0.5) 128 3,214 (81,633) RLL C DLTapeIV(20) 6,7 2760x1B 12.7 (0.5) 208 3,383 (85,937) RLL C DLTapeIV(35) 6,7 2770x1C 6.3 (0.25) 34 1,654 (42,000) MFM C QIC-385M 1,6 2780x1D 6.3 (0.25) 32 1,512 (38,400) GCR C QIC-410M 1,6 2790x1E 6.3 (0.25) 30 1,385 (36,000) GCR C QIC-1000C 1,6 2800x1F 6.3 (0.25) 30 2,666 (67,733) RLL C QIC-2100C 1,6 2810x20 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-6GB(M) 1,6 2820x21 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-20GB(C) 1,6 2830x22 6.3 (0.25) 42 1,600 (40,640) GCR C QIC-2GB(C) ? 2840x23 6.3 (0.25) 38 2,666 (67,733) RLL C QIC-875M ? 2850x24 3.81 (0.15) 1 2,400 (61,000) CS DDS-2 5 2860x25 3.81 (0.15) 1 3,816 (97,000) CS DDS-3 5 2870x26 3.81 (0.15) 1 3,816 (97,000) CS DDS-4 5 2880x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth 5 2890x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224 1 2900x29 12.7 (0.5) 2910x2A 2920x2B 12.7 (0.5) 3 ? ? ? C X3.267 5 2930x41 12.7 (0.5) 208 3,868 (98,250) RLL C DLTapeIV(40) 6,7 2940x48 12.7 (0.5) 448 5,236 (133,000) PRML C SDLTapeI(110) 6,8 2950x49 12.7 (0.5) 448 7,598 (193,000) PRML C SDLTapeI(160) 6,8 296.Ed 297.Bd -literal -offset 3n 298Code Description Type Description 299---------------- ---------------- 300NRZI Non return to zero, change on ones R Reel-to-reel 301GCR Group code recording C Cartridge 302PE Phase encoded CS Cassette 303IMFM Inverted modified frequency modulation 304MFM Modified frequency modulation 305DDS DAT data storage 306RLL Run length limited 307PRML Partial Response Maximum Likelihood 308.Ed 309.Bd -literal -offset 3n 310NOTES 3111. Serial recorded. 3122. Parallel recorded. 3133. Old format known as QIC-11. 3145. Helical scan. 3156. This is not an American National Standard. The reference is based on 316 an industry standard definition of the media format. 3177. DLT recording: serially recorded track pairs (DLTapeIII and 318 DLTapeIV(20)), or track quads (DLTapeIV(35) and DLTapeIV(40)). 3198. Super DLT (SDLT) recording: 56 serially recorded logical tracks with 320 8 physical tracks each. 321.Ed 322.Sh ENVIRONMENT 323If the following environment variable exists, it is utilized by 324.Nm . 325.Bl -tag -width Fl 326.It Ev TAPE 327The 328.Nm 329utility checks the 330.Ev TAPE 331environment variable if the 332argument 333.Ar tapename 334is not given. 335.El 336.Sh FILES 337.Bl -tag -width /dev/*sa[0-9]*xx -compact 338.It Pa /dev/*wt* 339QIC-02/QIC-36 magnetic tape interface 340.It Pa /dev/*sa[0-9]* 341SCSI magnetic tape interface 342.El 343.Sh SEE ALSO 344.Xr dd 1 , 345.Xr ioctl 2 , 346.Xr ast 4 , 347.Xr mtio 4 , 348.Xr sa 4 , 349.Xr environ 7 350.Sh HISTORY 351The 352.Nm 353command appeared in 354.Bx 4.3 . 355.Pp 356Extensions regarding the 357.Xr st 4 358driver appeared in 359.Bx 386 0.1 360as a separate 361.Nm st 362command, and have been merged into the 363.Nm 364command in 365.Fx 2.1 . 366.Pp 367The former 368.Cm eof 369command that used to be a synonym for 370.Cm weof 371has been abandoned in 372.Fx 2.1 373since it was often confused with 374.Cm eom , 375which is fairly dangerous. 376