System Administration Commands rmt(1M)
NAME
rmt - remote magtape protocol module
SYNOPSIS
/usr/sbin/rmt
DESCRIPTION
rmt is a program used by the remote dump and restore pro-
grams in manipulating a magnetic tape drive through an
interprocess communication connection. rmt is normally
started up with an rexec(3SOCKET) or rcmd(3SOCKET) call.
The rmt program accepts requests that are specific to the
manipulation of magnetic tapes, performs the commands, then
responds with a status indication. All responses are in
ASCI and in one of two forms. Successful commands have
responses of:
Anumber\n where number is an ASCI representation of a
decimal number.
Unsuccessful commands are responded to with:
Eerror-number\nerror-message\n
where error-number is one of the possible error numbers
described in intro(3), and error-message is the
corresponding error string as printed from a call to
perror(3C).
The protocol consists of the following commands:
S\n Return the status of the open dev-
ice, as obtained with a MTIOCGET
ioctl call. If the operation was
successful, an "ack" is sent with
the size of the status buffer, then
the status buffer is sent (in
binary).
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System Administration Commands rmt(1M)
Cdevice\n Close the currently open device.
The device specified is ignored.
Ioperation\ncount\n Perform a MTIOCOP ioctl(2) command
using the specified parameters. The
parameters are interpreted as the
ASCI representations of the
decimal values to place in the
mtop and mtcount fields of the
structure used in the ioctl call.
When the operation is successful
the return value is the count
parameter.
Loffset\nwhence\n Perform an lseek(2) operation using
the specified parameters. The
response value is returned from the
lseek call.
Odevice\nmode\n Open the specified device using the
indicated mode. device is a full
pathname, and mode is an ASCI
representation of a decimal number
suitable for passing to open(9E).
If a device is already open, it is
closed before a new open is per-
formed.
Rcount\n Read count bytes of data from the
open device. rmt performs the
requested read(9E) and responds
with Acount-read\n if the read was
successful; otherwise an error in
standard format is returned. If the
read was successful, the data read
is sent.
Wcount\n Write data onto the open device.
rmt reads count bytes from the con-
nection, aborting if a premature
EOF is encountered. The response
value is returned from the
write(9E) call.
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System Administration Commands rmt(1M)
Any other command causes rmt to exit.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWrcmdc
SEE ALSO
ufsdump(1M), ufsrestore(1M), intro(3), ioctl(2), lseek(2),
perror (3C), rcmd(3SOCKET), rexec(3SOCKET), attributes(5),
mtio(7I), open(9E), read(9E), write(9E)
DIAGNOSTICS
All responses are of the form described above.
BUGS
Do not use this for a remote file access protocol.
SunOS 5.11 Last change: 6 Nov 2000 3
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