mtio(1)               UNIX System V(Essential Utilities)                mtio(1)


NAME
      mtio - magnetic tape input/output

SYNOPSIS
      mtio [ -i ifile ] [ -o ofile ] [ -n nbuf ] [ -b bufsiz ] [ -v ] [ -V
      vsize ]

DESCRIPTION
      The mtio command is an attempt to improve backup performance by allowing
      file system i/o to proceed concurrently with tape i/o.  The mtio command
      spawns a child process to read its input into a mapped file.  The parent
      process writes the data from the child to the command's output.  The two
      processes treat the mapped file as a queue of buffers to be read and
      written; the number and size of these buffers may be specified by the -n
      and -b arguments.

      The following options are recognized:

      -i ifile
            specifies the file from which mtio should read its input; if this
            is not specified, the standard input is used.  If the -i argument
            is specified, the mtio command will prompt for another volume when
            it gets an EOF or error when reading from ifile.

      -o ofile
            specifies the file onto which mtio should write its output; if this
            is not specified, the standard output is used.  If the -o argument
            is specified, the mtio command will prompt for another volume when
            it gets an error when writing to ofile.

      -b bufsiz
            specifies the internal buffer size used for reading and writing.
            This is not a blocking factor; partial records may be written on
            the output media due to EOF on either the input or output media,

      -n nbuf
            specifies the number of buffers to be used.

      -V vsize
            prints progress.  As each buffer is written, the number of vsize
            units of data is displayed as d.ddd; e.g., if vsize is 1MB and
            2.5MB data has been written, ``[2.500]'' is displayed.  The vsize
            argument is a number optionally follwed by ``b'', ``k'', or ``m'',
            meaning 512-, 1024-, or 1048576-byte units, respectively.

      -v    prints progress in the default size (1M).

      -f temp
            allows specification of the temporary file.





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mtio(1)               UNIX System V(Essential Utilities)                mtio(1)


EXAMPLE
      A typical use of the mtio command is:
            find /home -print | cpio -oc | mtio -v -o /dev/tape
      The number of megabytes of data written to tape will be displayed.  When
      the tape fills, the mtio command will prompt for the insertion of a new
      tape.

SEE ALSO
      dd(1), find(1), cpio(1).













































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