rmt(1M)

NAME

     rmt - remote magtape protocol module

SYNOPSIS

     /usr/sbin/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(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\n error-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 success-
           ful, 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  pass-
           ing  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.

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWrcmdc                   |
    |_____________________________|_____________________________|

SEE ALSO

     ufsdump(1M), ufsrestore(1M), intro(3),  ioctl(2),  lseek(2),
     perror  (3C),  rcmd(3SOCKET), rexec(3SOCKET), attributes(5),
     mtio(7I), 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.