RMT(8) Maintenance Commands and Procedures RMT(8)
NAME
rmt - remote magtape protocol module
SYNOPSIS
/usr/sbin/rmtDESCRIPTION
rmt is a program used by the remote dump and restore programs 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
ASCII and in one of
two forms. Successful commands have responses of:
Anumber\n where
number is an
ASCII 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 device, 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).
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
ASCII representations of
the decimal values to place in the
mt_op and
mt_count 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
ASCII 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 performed.
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 connection, aborting if
a premature
EOF is encountered. The response
value is returned from the
write(9E) call.
Any other command causes
rmt to exit.
SEE ALSO
ioctl(2),
lseek(2),
Intro(3),
perror(3C),
rcmd(3SOCKET),
rexec(3SOCKET),
mtio(4I),
attributes(7),
ufsdump(8),
ufsrestore(8),
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.
November 6, 2000 RMT(8)
