wmtd(1M)                   DG/UX 4.30                    wmtd(1M)



     NAME
          wmtd - start the WORM magnetic tape device server

     SYNOPSIS
          /usr/sbin/wmtd wdevice=pdevice ...

          wdevice Device number in the /dev/wmt directory
          pdevice Pathname of the physical device

     DESCRIPTION
          A WORM drive is a write-once read-many disk device.  The
          WORM as magnetic tape server (daemon), wmtd, is designed to
          make, as much as possible, a WORM disk device act like a
          magnetic tape device.  From the user's perspective, all of
          the system tape archiving commands, such as mt(1),
          dump2(1M), restore(1M), and sysadm(1M) will behave as they
          do when archiving to magnetic tapes.  An exception to this
          rule is that a WORM disk may be written only once, a feature
          that makes WORM drives a good choice for permanent archives.

          A user opens a special file in the directory /dev/wmt.  The
          DG/UX kernel then communicates with the wmtd process to
          perform operations on the WORM device.  The wmtd process
          knows the physical device with which to communicate by the
          logical-to-physical device mappings specified on the
          command-line.  For example, if the system administrator
          wants /dev/wmt/0 and /dev/wmt/0n to be associated with the
          device, /dev/rpdsk/2, then the mapping would be
          0=/dev/rpdsk/2.  More than one device mapping may be
          specified when the system has more than one WORM device, but
          only one device may be accessed at a time.

          The wmtd server automatically puts itself in the background
          and detaches from any controlling terminal.  Unanticipated
          errors are communicated to the system through syslogd(8).
          Only a superuser can start the wmtd program.

          The prefered way to start the server is to let the system
          start it at boot time.  To have the system start wmtd, the
          system administrator must modify the /etc/dgux.params
          initialization file.  The variable wmtdSTART should be set
          to "true" and the wmtdARG should contain the command line
          arguments.

          The protocol used between wmt(7) and wmtd is the same
          protocol used by pmtd(1M).

     FILES
          /usr/include/sys/errno.h   File describing DG/UX errno values.

     SEE ALSO
          pmtd(1M), mt(1), dump2(1M), restore(1M), sysadm(1M),



     Licensed material--property of copyright holder(s)         Page 1

     wmtd(1M)                   DG/UX 4.30                    wmtd(1M)



          cpio(1), kill(2), ioctl(2), wmt(7), syslogd(8).

     CAVEATS
          The ioctl(2) operations (with the command MTIOCTOP)
          supported by the wmtd server are as follows:  MTFSF, MTBSF,
          MTREW, MTOFFL, MTWEOF, and MTNOP.

          If a /dev/wmt device is specified as the input-output device
          using one of the archiving commands and no valid mapping
          exists, wmtd returns ENODEV (in errno) to the calling
          process.

          The superuser should never send a SIGKILL (i.e. kill -9)
          signal to wmtd.  A SIGTERM (i.e. kill with no options)
          signal will allow the server to "clean up" any read or write
          that may be in progress.  If the server is sent a SIGKILL
          signal when writing, the remainder of the WORM cartridge
          will most likely be unusable.

          When using cpio(1), the superuser should specify the -B
          switch, as the wmtd server is slow when using small buffers.
          For maximum efficiency, the buffer size should be a multiple
          of the WORM device's sector size.
































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