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.\" @(#)mt.1 6.7 (Berkeley) 7/28/91
.Nd magnetic tape manipulating program
is used to give commands to a magnetic tape drive.
performs the requested operation once. Operations
may be performed multiple times by specifying
must reference a raw (not block) tape device.
The tape drive will hold density and blocking parameters until the next
unmount. In the case of rst0, this is immediatly and is therefore of
not much use with this device. In the case of nrst0 this
may be after several commands when either an offline command is issued or
rst0 is openned and closed. If parameters are to be held across
unmounts, then they should be made to the control device for each
mode.. i.e. the devices with a submode of 3 (minors 3,7,11,15 for example).
It is suggested that the operator keep the control device unreadble
and unwritable to normal system users, while giving them access to
the non-rewind device (e.g. nrst0) on demand.
The available commands are listed below. Only as many
characters as are required to uniquely identify a command
.Bl -tag -width "eof, weof"
end-of-file marks at the current position on the tape.
Rewind the tape and place the tape unit off-line (possibly eject)
Sets the block size characteristics of the openned
device to value specified in
A 0 means variable sized blocks, and anything else means fixed block,
with blocksize as that of
Set the density for the openned device (bits 2,3 of minor number)
density code as specified by the SCSI II specification. Valid values
.It The different density codes are as follows:
Value Tracks Density(bpi) Code Type Reference Note
0x1 9 800 NRZI R X3.22-1983 2
0x2 9 1600 PE R X3.39-1986 2
0x3 9 6250 GCR R X3.54-1986 2
0x5 4/9 8000 GCR C X3.136-1986 1
0x6 9 3200 PE R X3.157-1987 2
0x7 4 6400 IMFM C X3.116-1986 1
0x8 4 8000 GCR CS X3.158-1986 1
0x9 18 37871 GCR C X3B5/87-099 2
0xA 22 6667 MFM C X3B5/86-199 1
0xB 4 1600 PE C X3.56-1986 1
0xC 24 12690 GCR C HI-TC1 1,5
0xD 24 25380 GCR C HI-TC2 1,5
0xF 15 10000 GCR C QIC-120 1,5
0x10 18 10000 GCR C QIC-150 1,5
0x11 26 16000 GCR C QIC-320(525?) 1,5
0x12 30 51667 RLL C QIC-1350 1,5
0x13 1 61000 DDS CS X3B5/88-185A 4
0x14 1 43245 RLL CS X3.202-1991 4
0x15 1 45434 RLL CS ECMA TC17 4
0x16 48 10000 MFM C X3.193-1990 1
0x17 48 42500 MFM C X3B5/91-174 1
NRZI Non Return to Zero, change on ones
IMFM Inverted Modified Frequency Modulation
MFM Modified Frequency Modulation
3 Old format know as QIC-11
5 Not ANSI standard, rather industry standard.
Print status information about the tape unit.
Information is printed out about the present active parameters and
also the four Operating modes available.
If a tape name is not specified, and the environment variable
returns a 0 exit status when the operation(s) were successful,
1 if the command was unrecognized, and 2 if an operation failed.
If the following environment variable exists, it is utilized by
environment variable if the
.Bl -tag -width /dev/rmt* -compact
Raw magnetic tape interface
command appeared in 386BSD 0.1.
.\" mt.1: mtio(4) missing
projects / unix-history / blob