RMT(8) Maintenance 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)