RMT(8N)                 COMMAND REFERENCE                 RMT(8N)



NAME
     rmt - remote magtape protocol module

SYNOPSIS
     /etc/rmt

DESCRIPTION
     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(3n) or rcmd(3n) call.

     The rmt program accepts requests 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(2) and error-message is the corresponding
     error string as printed from a call to perror(3c).  The
     protocol 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.



Printed 10/17/86                                                1

RMT(8N)                 COMMAND REFERENCE                 RMT(8N)



     R count
         Read count bytes of data from the open 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.

RETURN VALUE
     [0] Rmt was successful.

     [1] Rmt was unsuccessful.

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

SEE ALSO
     rcmd(3n), rexec(3n), rdump(8n), rrestore(8n).

















Printed 10/17/86                                                2

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de:264,2336;2744,1318;
di:4062,131;
rv:4193,177;
ca:4370,139;
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