1.\" $NetBSD: mt.1,v 1.36 2012/03/19 10:48:20 njoly Exp $ 2.\" 3.\" Copyright (c) 1981, 1990, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)mt.1 8.1 (Berkeley) 6/6/93 31.\" 32.Dd March 9, 2008 33.Dt MT 1 34.Os 35.Sh NAME 36.Nm mt 37.Nd magnetic tape manipulation 38.Sh SYNOPSIS 39.Nm 40.Op Fl f Ar tapename 41.Ar command 42.Op Ar count 43.Sh DESCRIPTION 44The 45.Nm 46program is used to give commands to a magnetic tape drive. 47By default 48.Nm 49performs the requested operation once. 50Operations may be performed multiple times by specifying 51.Ar count . 52.Pp 53Note 54that 55.Ar tapename 56must reference a raw (not block) tape device. 57If 58.Ar tapename 59is of the form 60.Qq host:tapename , 61or 62.Qq user@host:tapename , 63.Nm 64writes to the named tape device on the remote host using 65.Xr rmt 8 . 66.Pp 67The 68.Xr rmt 8 69process on the remote host is typically initiated via 70.Xr rsh 1 , 71although an alternate method such as 72.Xr ssh 1 73can be specified via the 74.Ev RCMD_CMD 75environment variable. 76.Pp 77The available commands are listed below. 78Only as many characters as are required to uniquely identify a command 79need be specified. 80.Bl -tag -width "eof, weof" 81.It Cm asf 82Move forward 83.Ar count 84files from the beginning of the tape. 85This is accomplished by a rewind followed by fsf 86.Ar count . 87.It Cm eof , weof 88Write 89.Ar count 90end-of-file marks at the current position on the tape. 91.It Cm fsf 92Forward space 93.Ar count 94files. 95.It Cm fsr 96Forward space 97.Ar count 98records. 99.It Cm bsf 100Back space 101.Ar count 102files. 103.It Cm bsr 104Back space 105.Ar count 106records. 107.It Cm rewind 108Rewind the tape. 109(The 110.Ar count 111is ignored.) 112.It Cm offline , rewoffl 113Rewind the tape and place the tape unit off-line. 114Where supported, this ejects the tape. 115(The 116.Ar count 117is ignored.) 118.It Cm status 119Print status information about the tape unit. 120(The 121.Ar count 122is ignored.) 123.It Cm retension 124Retensions the tape. 125Not all tape drives support this feature. 126(The 127.Ar count 128is ignored.) 129.It Cm erase 130Erases the tape 131Not all tape drives support this feature. 132(The 133.Ar count 134is ignored.) 135.It Cm eew 136Enable or disable early warning EOM behaviour. 137Set 138.Ar count 139to nonzero to enable, zero to disable. 140.It Cm eom 141Forward space to the end of recorded media. 142(The 143.Ar count 144is ignored.) 145.It Cm blocksize , setblk 146Set the tape blocksize to 147.Ar count 148bytes. 149A 150.Ar count 151of zero sets variable blocksize. 152.It Cm density , setdensity 153Set the tape density code to 154.Ar count 155as specified in the 156.Tn SCSI-3 157specification. 158See the 159.Sx DENSITY CODES 160section for a list of codes for commonly used media types. 161.It Cm rdspos 162Read the logical block position of the tape. 163Not all tape drives support this feature. 164(The 165.Ar count 166is ignored.) 167.It Cm rdhpos 168Read the hardware block position of the tape. 169Not all tape drives support this feature. 170(The 171.Ar count 172is ignored.) 173.It Cm setspos 174Set the logical block position of the tape to 175.Ar count . 176Not all tape drives support this feature. 177.It Cm sethpos 178Set the hardware block position of the tape to 179.Ar count . 180Not all tape drives support this feature. 181.It Cm compress 182If 183.Ar count 184is zero, disable compression. 185Otherwise enable compression. 186Not all tape drives support this feature. 187.El 188.Pp 189If a tape name is not specified, and the environment variable 190.Ev TAPE 191is not set, then 192.Nm 193uses the device 194.Pa /dev/nrst0 . 195.Sh ENVIRONMENT 196If the following environment variables exist, they are used by 197.Nm . 198.Bl -tag -width Fl 199.It Ev TAPE 200.Nm 201uses device filename given in the 202.Ev TAPE 203environment variable if the 204.Ar tapename 205argument is not given. 206.It Ev RCMD_CMD 207.Nm 208will use 209.Ev RCMD_CMD 210rather than 211.Pa /usr/bin/rsh 212to invoke 213.Xr rmt 8 214on a remote machine. 215The full path name must be specified. 216.El 217.Sh FILES 218.Bl -tag -width /dev/rst* -compact 219.It Pa /dev/rst* 220Raw 221.Tn SCSI 222tape device 223.It Pa /dev/rmt* 224Raw magnetic tape device 225.El 226.Sh EXIT STATUS 227.Nm 228returns a 0 exit status when the operation(s) were successful, 2291 if the command was unrecognized, and 2 if an operation failed. 230.Sh DENSITY CODES 231The SCSI-3 specification defines a number of density codes for 232various tape media, some of which are listed here. 233Note that many tape drive vendors also define model-specific codes. 234.Pp 235.Bl -column "Code" "Format" -compact 236.It Em Code Ta Em Format 237.It Li 0 Ta Device default 238.It Li 1 Ta 1/2" 800 bpi 239.It Li 2 Ta 1/2" 1600 bpi 240.It Li 3 Ta 1/2" 6250 bpi 241.It Li 4 Ta QIC-11 242.It Li 5 Ta QIC-24 243.It Li 15 Ta QIC-120 244.It Li 16 Ta QIC-150 245.It Li 17 Ta QIC-320/525 246.It Li 18 Ta QIC-1320/1350 247.It Li 19 Ta DDS 248.It Li 28 Ta QIC-385M 249.It Li 29 Ta QIC-410M 250.It Li 30 Ta QIC-1000C 251.It Li 31 Ta QIC-2100C 252.It Li 32 Ta QIC-6GB 253.It Li 33 Ta QIC-20GB 254.It Li 34 Ta QIC-2GB 255.It Li 35 Ta QIC-875M 256.It Li 36 Ta DDS-2 257.It Li 37 Ta DDS-3 258.It Li 38 Ta DDS-4 259.El 260.Sh SEE ALSO 261.Xr dd 1 , 262.Xr ioctl 2 , 263.Xr mtio 4 , 264.Xr st 4 , 265.Xr environ 7 266.Sh HISTORY 267The 268.Nm 269utility appeared in 270.Bx 4.3 . 271