rmt(1M) rmt(1M)
NAME
rmt - remote magnetic-tape protocol module
SYNOPSIS
DESCRIPTION
is a program used by the remote dump and restore programs for manipulating a magnetic tape drive through an interprocess communication
(IPC) connection. The and commands also use to achieve remote backup capability (see fbackup(1M) and frecover(1M)). is normally started
up with an or call (see rexec(3N) and rcmd(3N)).
accepts requests specific to the manipulation of magnetic tapes, performs the commands, then responds with a status indication. DDS
devices that emulate magnetic tapes are also supported. All responses are in ASCII and in one of two forms. Successful commands have
responses of
where number is an ASCII representation of a decimal number. Unsuccessful commands are responded to with
where error-number is one of the possible error numbers described in errno(2) and error-message is the corresponding error string as
printed from a call to (see perror(3C)). The protocol is comprised of the following commands:
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 (see open(2)). If a device is already open, it is closed before a new open is
performed.
Open the specified device using the indicated mode. device is a full pathname and mode is an ASCII representation of an octal
number suitable for passing to If a device is already open, it is closed before a new open is performed.
Close the currently open device.
The device specified is ignored.
Perform an operation using the specified parameters (see lseek(2)). The response value is that returned from by
Write data onto the open device.
reads count bytes from the connection, aborting if a premature end-of-file is encountered. The response value
is that returned from by (see write(2)).
Read count bytes of data from the open device. If count exceeds the size of the data buffer (10 Kbytes), it is
truncated to the data buffer size. then performs the requested and responds with if the read was successful.
Otherwise an error is returned in the standard format. If the read was successful, the data read is then sent.
Perform a command using the specified parameters. Parameters are interpreted as ASCII representations of the decimal
values to be placed in the and fields of the structure used in the call. The return value is the count parame-
ter when the operation is successful.
Return the status of the open device, as obtained with a
call. If the operation was successful, an ACK is sent with the size of the status buffer, then the status buf-
fer is sent (in binary).
Return the status of the open device, as obtained with a
call. If the operation was successful, an ACK is sent with the size of the status buffer, then the status buf-
fer is sent (in binary). Return the status of the open device, as obtained with a call. If the operation was
successful, an ACK is sent with the size of the status buffer, then the status buffer is sent in the following
ASCII format:
machine<blank>value<newline>
stat_struct_member_name<blank>value<newline>
The end of the data is indicated by an ASCII NULL character. See for the definition. In addition to the
struct stat information, there is an entry in the buffer describing the machine type as returned from a call
(see uname(2)). In the above format ``machine'' is a key word. All fields except of the are returned.
Return the status of the open device, as obtained with a
call. If the operation was successful, an is sent with the size of the status buffer, then the status buffer
is sent in the following ASCII format:
machine<blank>value<newline>
mtget_struct_member_name<blank>value<newline>
The end of the data is indicated by an ASCII NULL character. See for the definition. In addition to the
struct mtget information there is an entry in the buffer describing the machine type as returned from a call.
In the above format "machine" is a keyword.
Any other command causes to exit.
RETURN VALUE
Device status is returned in the field contains defined macros for checking the status bits.
DIAGNOSTICS
All responses are of the form described above.
WARNINGS
Use of this command for remote file access protocol is discouraged.
AUTHOR
was developed by the University of California, Berkeley.
SEE ALSO
ftio(1), fbackup(1M), frecover(1M), dump(1M), restore(1M), rcmd(3N), rexec(3N).
rmt(1M)