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 fsf 68Forward space 69.Ar count 70files. 71.It Cm fsr 72Forward space 73.Ar count 74records. 75.It Cm bsf 76Back space 77.Ar count 78files. 79.It Cm bsr 80Back space 81.Ar count 82records. 83.It Cm rewind 84Rewind the tape 85(Count is ignored). 86.It Cm offline , rewoffl 87Rewind the tape and place the tape unit off-line 88(Count is ignored). 89.It Cm erase 90Erase the tape. 91A count of 0 disables long erase, which is on by default. 92.It Cm retension 93Re-tension the tape 94(one full wind forth and back, Count is ignored). 95.It Cm status 96Print status information about the tape unit. 97.It Cm blocksize 98Set the block size for the tape unit. Zero means variable-length 99blocks. 100.It Cm density 101Set the density for the tape unit. For the density codes, see below. 102The density value could be given either numerically, or as a string, 103corresponding to the 104.Dq Reference 105field. If the string is abbreviated, it will be resolved in the order 106shown in the table, and the first matching entry will be used. If the 107given string and the resulting canonical density name do not match 108exactly, an informational message is printed about what the given 109string has been taken for. 110.It Cm eom 111Forward space to end of recorded medium 112(Count is ignored). 113.It Cm eod 114Forward space to end of data, identical to 115.Cm eom . 116.It Cm comp 117Set compression mode. 118There are currently several possible values for the compression mode: 119.Pp 120.Bl -tag -width 123456789 -compact 121.It off 122Turn compression off 123.It on 124Turn compression on 125.It none 126Same as 127.Ar off 128.It enable 129Same as 130.Ar on 131.It IDRC 132IBM Improved Data Recording Capability compression (0x10). 133.It DCLZ 134DCLZ compression algorithm (0x20). 135.El 136.Pp 137In addition to the above recognized compression keywords, the user can 138supply a numeric compression algorithm for the tape drive to use. In most 139cases, simply turning the compression 140.Sq on 141will have the desired effect of enabling the default compression algorithm 142supported by the drive. If this is not the case (see the 143.Cm status 144display to see which compression algorithm is currently in use), the user 145can manually specify one of the supported compression keywords (above), or 146supply a numeric compression value. 147.El 148.Pp 149If a tape name is not specified, and the environment variable 150.Ev TAPE 151does not exist; 152.Nm 153uses the device 154.Pa /dev/nrsa0 . 155.Pp 156.Nm Mt 157returns a 0 exit status when the operation(s) were successful, 1581 if the command was unrecognized, and 2 if an operation failed. 159.Pp 160The following density table was taken from the 161.Sq Historical sequential access density codes 162table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC) 163working draft, dated November 11, 1997. 164.Pp 165The different density codes are as follows: 166.Pp 167.Dl 0x0 default for device 168.Dl 0xE reserved for ECMA 169.Bd -literal -offset 3n 170Value Width Tracks Density Code Type Reference Note 171 mm in bpmm bpi 1720x01 12.7 (0.5) 9 32 (800) NRZI R X3.22-1983 2 1730x02 12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2 1740x03 12.7 (0.5) 9 246 (6,250) GCR R X3.54-1986 2 1750x05 6.3 (0.25) 4/9 315 (8,000) GCR C X3.136-1986 1 1760x06 12.7 (0.5) 9 126 (3,200) PE R X3.157-1987 2 1770x07 6.3 (0.25) 4 252 (6,400) IMFM C X3.116-1986 1 1780x08 3.81 (0.15) 4 315 (8,000) GCR CS X3.158-1987 1 1790x09 12.7 (0.5) 18 1,491 (37,871) GCR C X3.180 2 1800x0A 12.7 (0.5) 22 262 (6,667) MFM C X3B5/86-199 1 1810x0B 6.3 (0.25) 4 63 (1,600) PE C X3.56-1986 1 1820x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1 1,6 1830x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2 1,6 1840x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120 1,6 1850x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150 1,6 1860x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320 1,6 1870x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350 1,6 1880x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A 5 1890x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5 1900x15 8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 1910x16 12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1 1920x17 12.7 (0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1 1930x18 12.7 (0.5) 112 1,673 (42,500) MFM C X3B5/92-50 1 1940x1C 6.3 (0.25) 34 1,654 (42,000) MFM C QIC-385M 1,6 1950x1D 6.3 (0.25) 32 1,512 (38,400) GCR C QIC-410M 1,6 1960x1E 6.3 (0.25) 30 1,385 (36,000) GCR C QIC-1000C 1,6 1970x1F 6.3 (0.25) 30 2,666 (67,733) RLL C QIC-2100C 1,6 1980x20 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-6GB(M) 1,6 1990x21 6.3 (0.25) 144 2,666 (67,733) RLL C QIC-20GB(C) 1,6 2000x22 6.3 (0.25) 42 1,600 (40,640) GCR C QIC-2GB(C) ? 2010x23 6.3 (0.25) 38 2,666 (67,733) RLL C QIC-875M ? 2020x24 3.81 (0.15) 1 2,400 (61,000) CS DDS-2 5 2030x25 3.81 (0.15) 1 3,816 (97,000) CS DDS-3 5 2040x26 3.81 (0.15) 1 3,816 (97,000) CS DDS-4 5 2050x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth 5 2060x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224 1 2070x29 12.7 (0.5) 2080x2A 2090x2B 12.7 (0.5) 3 ? ? ? C X3.267 5 210.Ed 211 212.Bd -literal -offset 3n 213Code Description Type Description 214---------------- ---------------- 215NRZI Non return to zero, change on ones R Reel-to-reel 216GCR Group code recording C Cartridge 217PE Phase encoded CS Cassette 218IMFM Inverted modified frequency modulation 219MFM Modified frequency modulation 220DDS DAT data storage 221RLL Run length limited 222.Ed 223 224.Bd -literal -offset 3n 225NOTES 2261. Serial recorded. 2272. Parallel recorded. 2283. Old format known as QIC-11. 2295. Helical scan. 2306. This is not an American National Standard. The reference is based on 231 an industry standard definition of the media format. 232.Ed 233 234.Sh ENVIRONMENT 235If the following environment variable exists, it is utilized by 236.Nm mt . 237.Bl -tag -width Fl 238.It Ev TAPE 239.Nm Mt 240checks the 241.Ev TAPE 242environment variable if the 243argument 244.Ar tapename 245is not given. 246.Sh FILES 247.Bl -tag -width /dev/*rst[0-9]*xx -compact 248.It Pa /dev/*rwt* 249QIC-02/QIC-36 magnetic tape interface 250.It Pa /dev/*rsa[0-9]* 251SCSI magnetic tape interface 252.El 253.Sh SEE ALSO 254.Xr dd 1 , 255.Xr ioctl 2 , 256.Xr mtio 4 , 257.Xr st 4 , 258.Xr wt 4 , 259.Xr environ 7 260.Sh HISTORY 261The 262.Nm 263command appeared in 264.Bx 4.3 . 265.Pp 266Extensions regarding the 267.Xr st 4 268driver appeared in 386BSD 0.1 as a separate 269.Xr st 1 270command, and have been merged into the 271.Nm 272command in 273.Fx 2.1 . 274.Pp 275The former 276.Cm eof 277command that used to be a synonym for 278.Cm weof 279has been abandoned in 280.Fx 2.1 281since it was often confused with 282.Cm eom , 283which is fairly dangerous. 284