sys/i386/doc/wt.doc

This is the streamer tape driver for 386bsd and FreeBSD, which
supports Wangtek and Archive compatible QIC-02/QIC-36 controllers.
It was developed as a replacement of the old Wangtek tape driver from CMU.

In comparison with the CMU driver, this version has the following enhancements:
1) Support for Archive SC402 and SC499 tape controllers added.
2) Support for up to three tape controllers on the same machine.
3) Support for BSD-style ioctls MTIOCGET, MTIOCTOP.
   Mt command now works adequately with this driver.
2) Asynchronous REWIND and FSF operations, close() will not wait
   until they finish.  The next open() will wait for it instead.
4) Use of WTQICMD ioctl is limited to ERASE and RETENS operations.
   This prevents the user from locking the tape driver by strange
   tape operations.
5) Tape density switching added.
6) The status of the process, blocked on the tape operation,
   is displayed at the WCHAN column of the `ps' command as:

        wtread    reading data from the tape
        wtwrite   writing data to the tape
        wtrfm     reading the tape marker
        wtwfm     writing the tape marker
        wtrew     rewinding the tape
        wterase   doing WTQICMD ERASE operation
        wtretens  doing WTQICMD RETENS operation
        wtorew    doing MTIOCTOP REW/OFFL operation
        wtorfm    doing MTIOCTOP FSF operation
        wtowfm    doing MTIOCTOP WEOF operation

7) It's possible to use the tape with "default density",
   useful for devices which don't support density switching
   or do automatic format determination.
8) Some controllers support only 1024 block length.
   Setting WT_BSIZE bit in device minor number turns on this mode.

Minor number structure:
        0bfffuuu
Fields:
        uuu   - Unit number. It's possible to install
                up to three tape controllers on the same machine,
                using DRQs 1..3.  Hence, unit number can lie
                in range 0..2.
        fff   - Tape format number:
                0 - /dev/rwt0  - default density (auto select)
                1 - /dev/rwt0a - QIC 11 (obsolete)
                2 - /dev/rwt0b - QIC 24 (60 megabytes)
                3 - /dev/rwt0c - QIC 120 (120 megabytes)
                4 - /dev/rwt0d - QIC 150 (150 megabytes)
                5 - /dev/rwt0e - QIC 300 (300 megabytes?)
                6 - /dev/rwt0f - QIC 600 (600 megabytes?)
        b     - Long block size flag.  With this bit set,
                the driver will perform all i/o operations
                with the controller using 1024-byte
                blocks, instead of 512 ones.
                Some controllers need it (CMS for example).
                If you Wangtek controller does not stream well,
                you can try to use /dev/rWt0 device instead
                of /dev/rwt0 (uncomment needed lines in /dev/MAKEDEV
                to create it).

Block interface (writing blocks less than 2048 bytes) is not functioning
pwoperly.  Use raw interface instead.

Thanks to all who helped to test it on the following hardware:

Controller           Drive            Volume    Interface     Thanks to
---------------------------------------------------------------------------
Archive SC-499       Archive 2150L    150 Meg   QIC-02        KIAE
CMS?                 ?                150 Meg   QIC-02        KIAE
Everex EV 831/833    ?                ?         QIC-36        Joergen Haegg
Wangtek ASSY         Wangtek          60 Meg    QIC-02        Ken Whedbee
Tecmar QT150i?       Wangtek 5150EQ   ?         QIC-02?       Marko Teiste
?                    Wangtek 5099EK   60 Meg    QIC-36        Robert Shien
Archive SC400S       ?                60 Meg    ?             Warren Toomey

Sergey Ryzhkov, Serge Vakulenko
E-mail: <sir@kiae.su>, <vak@zebub.msk.su>