RMT(8C-BSD)         RISC/os Reference Manual          RMT(8C-BSD)



NAME
     rmt - remote magtape protocol module

SYNOPSIS
     /etc/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(3) or rcmd(3) call.

     The rmt program accepts requests specific to the manipula-
     tion 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(2) and error-message is the corresponding
     error string as printed from a call to perror(3).  The pro-
     tocol is comprised of the following commands (a space is
     present between each token).

     O device mode  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(2).  If a device
                    had already been opened, it is closed before
                    a new open is performed.

     C device       Close the currently open device.  The device
                    specified is ignored.

     L whence offset
                    Perform an lseek(2) operation using the
                    specified parameters.  The response value is
                    that returned from the lseek call.

     W count        Write data onto the open device.  rmt reads
                    count bytes from the connection, aborting if
                    a premature end-of-file is encountered.  The
                    response value is that returned from the
                    write(2) call.

     R count        Read count bytes of data from the open



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RMT(8C-BSD)         RISC/os Reference Manual          RMT(8C-BSD)



                    device.  If count exceeds the size of the
                    data buffer (10 kilobytes), it is truncated
                    to the data buffer size.  rmt then performs
                    the requested read(2) and responds with
                    Acount-read\n if the read was successful;
                    otherwise an error in the standard format is
                    returned.  If the read was successful, the
                    data read is then sent.

     I operation count
                    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.  The return value is the count
                    parameter when the operation is successful.

     S              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).

     Any other command causes rmt to exit.

DIAGNOSTICS
     All responses are of the form described above.

SEE ALSO
     rdump(1M), rrestore(1M), mtio(7).
     rcmd(3), rexec(3) in the Programmer's Reference Manual.

BUGS
     People tempted to use this for a remote file access protocol
     are discouraged.



















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