wmtd(1M)                       DG/UX 5.4R3.00                       wmtd(1M)


NAME
       wmtd - start the WORM magnetic tape device server

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

   where:
       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(1M).  Only a superuser can
       start the wmtd program.

       The preferred 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), cpio(1),
       kill(2), ioctl(2), wmt(7), syslogd(1M).





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wmtd(1M)                       DG/UX 5.4R3.00                       wmtd(1M)


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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