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  man pages->Tru64 Unix man pages -> rmt (8)              



NAME    [Toc]    [Back]

       rmt - Allows remote access to magnetic tape devices

SYNOPSIS    [Toc]    [Back]

       rmt [debug-output-file]

DESCRIPTION    [Toc]    [Back]

       The  rmt  command  is  started  as  a  server process when
       requests from an rdump or rrestore call enter  the  system
       to operate a storage device through an interprocess communications
 connection. After the remote programs have  finished,
  rmt  exits  and  will be started again at the next
       request.  The rmt command  is  normally  invoked  with  an
       rexec or rcmd system call.

       This  process  performs the commands described in the following
 table and responds with a status indication to tell
       a  user  the result of the commanded process. When the rmt
       command is called with a filename specified as the  debugoutput-file
  parameter, all status responses are passed to
       the debug-output-file in ASCII and in one of two  possible
       formats.   Consequently,  a system administrator can debug
       both software and hardware problems associated with previously
 issued backup commands to storage devices.

       Responses to successful commands are in the format:


       where A identifies a normal response, number is an integer
       that defines the number of the response as an ASCII  integer,
 and \n is a newline in the C-language idiom.

       Responses to unsuccessful commands are in the format:

       Eerror_number  error_message\n

       where E identifies a response to an error, error_number is
       one of the possible  error  numbers  values  described  in
       intro(2), error_message is the corresponding error-message
       string, which is output in response  to  a  call  to  perror(3), and\n is a newline.

       Debug  information  returned by rmt is stored in the named
       debug-output-file file. The rmt command is called from the
       rdump  or rrestore process with no file argument only when
       the debug-output-file parameter is specified.  To activate
       the  debug  option of rmt your system administrator should
       rename the original rmt to rmt.ORG, for example, and  create
  a  new shell executable rmt that calls rmt.ORG debugoutput-file.


       The rdump command starts remote  server  /usr/sbin/rmt  or
       /etc/rmt  on  the  client  machine  to  access the storage
       medium. Another vendor's rdump command  may  fail  because
       rmt is not located in /etc.  To avoid this problem, it may
       be necessary to provide a symbolic link on the Tru64  UNIX
       machine  pointing to /usr/sbin/rmt as shown in the following
 example: ln -s /usr/sbin/rmt /etc/rmt

       All numerical arguments  of  the  following  commands  are
       transferred as ASCII strings: Opens the device, which must
       be a full pathname. The option parameter is a option value
       suitable for the open system call. When the device is successfully
 opened, the response is A0\n.  Closes  the  current
  open  device.  When  this command is successful, the
       response is A0\n.  Performs a seek operation.  The  offset
       and  whence  parameters  have the same significance as the
       offset and whence parameters of  the  lseek  system  call.
       When  this command successfully completes, the response is
       An\n, where n has the same value returned  by  a  normally
       successful  lseek  system call.  Writes data to the device
       (see the O command above). The  rmt  command  reads  count
       bytes from the connection. This process is aborted when an
       EOF (End-of-File) is detected before the number of characters
  specified  by  count is transferred. The response to
       this command is An\n, where n is the number of  characters
       written.   Reads count bytes of data from the open device.
       When the value of count  exceeds  the  size  of  the  data
       buffer  (10  kilobytes),  the number of characters read is
       truncated to the data buffer size. The  rmt  command  then
       does  the  requested  read operation. The response to this
       command is An\n, where n is the number of characters read.
       Performs  an  ioctl  system  call  on the open device. The
       operation parameter is a value passed to the mt_op  member
       of  a  type mtop structure for an MTIOCTOP ioctl (magnetic
       tape operation) command. Valid  values  for  the  magnetic
       tape operations are defined in the /usr/include/sys/mtio.h
       include file.  The count parameter is the value to pass to
       the  mt_count member of the type mtop structure and specifies
 the number of operations performed on the tape drive.
       The  response  to  this  command  is  An\n, where n is the
       count.  Returns the status of the open  device,  which  is
       obtained  with  a MTIOCGET ioctl system call. A successful
       response to this command is An\n, where n is the  size  of
       the  status buffer, together with the contents of the status
 buffer in binary.

FILES    [Toc]    [Back]

       Specifies the command path Describes  the  possible  error
       numbers  A  header  file that defines magnetic tape operations

SEE ALSO    [Toc]    [Back]

       Commands: rdump(8), rrestore(8)

       Functions: rcmd(3), rexec(3), open(2), ioctl(2)

[ Back ]
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