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.\" 35.Dd June 6, 1993 36.Dt MT 1 37.Os BSD 4 38.Sh NAME 39.Nm mt 40.Nd magnetic tape manipulating program 41.Sh SYNOPSIS 42.Nm 43.Op Fl f Ar tapename 44.Ar command 45.Op Ar count 46.Sh DESCRIPTION 47.Nm Mt 48is used to give commands to a magnetic tape drive. 49By default 50.Nm 51performs the requested operation once. Operations 52may be performed multiple times by specifying 53.Ar count . 54Note 55that 56.Ar tapename 57must reference a raw (not block) tape device. 58.Pp 59The available commands are listed below. Only 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. Some drives do not support this. The block 97number reported is specific for that hardware only. The count argument is 98ignored. 99.It Cm rdspos 100Read SCSI logical block position. Some drives do not support this. The 101count argument is ignored. 102.It Cm sethpos 103Set Hardware block position. Some drives do not support this. The count 104argument is interpreted as a hardware block to which to position the tape. 105.It Cm setspos 106Set SCSI logical block position. Some drives do not support this. The count 107argument is interpreted as a SCSI logical block to which to position the tape. 108.It Cm rewind 109Rewind the tape 110(Count is ignored). 111.It Cm offline , rewoffl 112Rewind the tape and place the tape unit off-line 113(Count is ignored). 114.It Cm erase 115Erase the tape. 116A count of 0 disables long erase, which is on by default. 117.It Cm retension 118Re-tension the tape 119(one full wind forth and back, Count is ignored). 120.It Cm status 121Print status information about the tape unit. For SCSI magnetic tape devices, 122the current operating modes of density, blocksize, and whether compression 123is enabled is reported. The current state of the driver (what it thinks that 124it is doing with the device) is reported. If the driver knows the relative 125position from BOT (in terms of filemarks and records), it prints that. Note 126that this information is not definitive (only BOT, End of Recorded Media, and 127hardware or SCSI logical block position (if the drive supports such) are 128considered definitive tape positions). 129.It Cm errstat 130Print (and clear) error status information about this device. For every normal 131operation (e.g., a read or a write) and every control operation (e.g,, a 132rewind), the driver stores up the last command executed and it's associated 133status and any residual counts (if any). This command retrieves and prints this 134information. If possible, this also clears any latched error information. 135.It Cm blocksize 136Set the block size for the tape unit. Zero means variable-length 137blocks. 138.It Cm density 139Set the density for the tape unit. For the density codes, see below. 140The density value could be given either numerically, or as a string, 141corresponding to the 142.Dq Reference 143field. If the string is abbreviated, it will be resolved in the order 144shown in the table, and the first matching entry will be used. If the 145given string and the resulting canonical density name do not match 146exactly, an informational message is printed about what the given 147string has been taken for. 148.It Cm geteotmodel 149Fetch and print out the current EOT filemark model. The model states how 150many filemarks will be written at close if a tape was being written. 151.It Cm seteotmodel 152Set (from the 153.Ar count 154argument) 155and print out the current and EOT filemark model. Typically this will be 156.Ar 2 157filemarks, but some devices (typically QIC cartridge drives) can 158only write 159.Ar 1 160filemark. Currently you can only choose a value of 161.Ar 1 162or 163.Ar 2 . 164.It Cm eom 165Forward space to end of recorded medium 166(Count is ignored). 167.It Cm eod 168Forward space to end of data, identical to 169.Cm eom . 170.It Cm comp 171Set compression mode. 172There are currently several possible values for the compression mode: 173.Pp 174.Bl -tag -width 123456789 -compact 175.It off 176Turn compression off 177.It on 178Turn compression on 179.It none 180Same as 181.Ar off 182.It enable 183Same as 184.Ar on 185.It IDRC 186IBM Improved Data Recording Capability compression (0x10). 187.It DCLZ 188DCLZ compression algorithm (0x20). 189.El 190.Pp 191In addition to the above recognized compression keywords, the user can 192supply a numeric compression algorithm for the tape drive to use. In most 193cases, simply turning the compression 194.Sq on 195will have the desired effect of enabling the default compression algorithm 196supported by the drive. If this is not the case (see the 197.Cm status 198display to see which compression algorithm is currently in use), the user 199can manually specify one of the supported compression keywords (above), or 200supply a numeric compression value. 201.El 202.Pp 203If a tape name is not specified, and the environment variable 204.Ev TAPE 205does not exist; 206.Nm 207uses the device 208.Pa /dev/nrsa0 . 209.Pp 210.Nm Mt 211returns a 0 exit status when the operation(s) were successful, 2121 if the command was unrecognized, and 2 if an operation failed. 213.Pp 214The following density table was taken from the 215.Sq Historical sequential access density codes 216table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC) 217working draft, dated November 11, 1997. 218.Pp 219The different density codes are as follows: 220.Pp 221.Dl 0x0 default for device 222.Dl 0xE reserved for ECMA 223.Bd -literal -offset 3n 224Value Width Tracks Density Code Type Reference Note 225 mm in bpmm bpi 2260x01 12.7 (0.5) 9 32 (800) NRZI R X3.22-1983 2 2270x02 12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2 2280x03 12.7 (0.5) 9 246 (6,250) GCR R X3.54-1986 2 2290x05 6.3 (0.25) 4/9 315 (8,000) GCR C X3.136-1986 1 2300x06 12.7 (0.5) 9 126 (3,200) PE R X3.157-1987 2 2310x07 6.3 (0.25) 4 252 (6,400) IMFM C X3.116-1986 1 2320x08 3.81 (0.15) 4 315 (8,000) GCR CS X3.158-1987 1 2330x09 12.7 (0.5) 18 1,491 (37,871) GCR C X3.180 2 2340x0A 12.7 (0.5) 22 262 (6,667) MFM C X3B5/86-199 1 2350x0B 6.3 (0.25) 4 63 (1,600) PE C X3.56-1986 1 2360x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1 1,6 2370x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2 1,6 2380x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120 1,6 2390x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150 1,6 2400x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320 1,6 2410x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350 1,6 2420x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A 5 2430x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5 2440x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 2450x16 12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1 2460x17 12.7 (0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1 2470x18 12.7 (0.5) 112 1,673 (42,500) MFM C X3B5/92-50 1 2480x1C 6.3 (0.25) 34 1,654 (42,000) MFM C QIC-385M 1,6 2490x1D 6.3 (0.25) 32 1,512 (38,400) GCR C QIC-410M 1,6 2500x1E 6.3 (0.25) 30 1,385 (36,000) GCR C QIC-1000C 1,6 2510x1F 6.3 (0.25) 30 2,666 (67,733) RLL C QIC-2100C 1,6 2520x20 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-6GB(M) 1,6 2530x21 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-20GB(C) 1,6 2540x22 6.3 (0.25) 42 1,600 (40,640) GCR C QIC-2GB(C) ? 2550x23 6.3 (0.25) 38 2,666 (67,733) RLL C QIC-875M ? 2560x24 3.81 (0.15) 1 2,400 (61,000) CS DDS-2 5 2570x25 3.81 (0.15) 1 3,816 (97,000) CS DDS-3 5 2580x26 3.81 (0.15) 1 3,816 (97,000) CS DDS-4 5 2590x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth 5 2600x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224 1 2610x29 12.7 (0.5) 2620x2A 2630x2B 12.7 (0.5) 3 ? ? ? C X3.267 5 264.Ed 265 266.Bd -literal -offset 3n 267Code Description Type Description 268---------------- ---------------- 269NRZI Non return to zero, change on ones R Reel-to-reel 270GCR Group code recording C Cartridge 271PE Phase encoded CS Cassette 272IMFM Inverted modified frequency modulation 273MFM Modified frequency modulation 274DDS DAT data storage 275RLL Run length limited 276.Ed 277 278.Bd -literal -offset 3n 279NOTES 2801. Serial recorded. 2812. Parallel recorded. 2823. Old format known as QIC-11. 2835. Helical scan. 2846. This is not an American National Standard. The reference is based on 285 an industry standard definition of the media format. 286.Ed 287 288.Sh ENVIRONMENT 289If the following environment variable exists, it is utilized by 290.Nm mt . 291.Bl -tag -width Fl 292.It Ev TAPE 293.Nm Mt 294checks the 295.Ev TAPE 296environment variable if the 297argument 298.Ar tapename 299is not given. 300.Sh FILES 301.Bl -tag -width /dev/*rst[0-9]*xx -compact 302.It Pa /dev/*rwt* 303QIC-02/QIC-36 magnetic tape interface 304.It Pa /dev/*rsa[0-9]* 305SCSI magnetic tape interface 306.El 307.Sh SEE ALSO 308.Xr dd 1 , 309.Xr ioctl 2 , 310.Xr mtio 4 , 311.Xr sa 4 , 312.Xr wt 4 , 313.Xr environ 7 314.Sh HISTORY 315The 316.Nm 317command appeared in 318.Bx 4.3 . 319.Pp 320Extensions regarding the 321.Xr st 4 322driver appeared in 386BSD 0.1 as a separate 323.Xr st 1 324command, and have been merged into the 325.Nm 326command in 327.Fx 2.1 . 328.Pp 329The former 330.Cm eof 331command that used to be a synonym for 332.Cm weof 333has been abandoned in 334.Fx 2.1 335since it was often confused with 336.Cm eom , 337which is fairly dangerous. 338