Here's the general idea:

  - Run 'hinv'. You should see your tape drive, with a meaningless guess
    as to its type. Note the SCSI controller number and ID. If you don't
    see it, fiddle with the hardware until you do.

  - Do 'cd /dev' and './MAKEDEV tape' to build a tape device for your
    tape. If you have only one tape drive, its device is /dev/tape. If
    you have more than one, its device is something like
    /dev/rmt/tpsAdB, where "tps" may be one of several abbreviations for
    the class of tape drive you have, A is the SCSI controller number
    and B is the SCSI ID.  There will be other devices with similar
    names; don't worry about them just yet.

  - Run 'mt -t <device> stat'. You should see something like

    % mt -t /dev/rmt/tps0d2
    Controller: SCSI
    Device: XXXXXX: YYYYYY
    Status: 0x202
    Drive type: unknown
    Media : Not READY

    Note "XXXXXX" and "YYYYYYY".

  - Edit /var/sysgen/master.d/scsi. Most of it is a list of tape drive
    types. Find a likely looking entry and copy it. Replace the fifth
    and sixth fields of the copied entry with "XXXXXX" and "YYYYYYY",
    and replace the third and fourth fields with the length in
    characters of "XXXXXX" and "YYYYYYY" respectively.

  - Rebuild your kernel, then do 'cd /dev' and './MAKEDEV tape'
    again. The same device files will be created, but they will behave
    correctly (if you got the /var/sysgen/master.d/scsi entry right).
    Check 'hinv' and 'mt -t <device> stat' again; you should see the
    correct tape name and so on.

  However, there are lots of details for particular drives.  Only part
  of the voluminous literature on the topic may be found at

      ftp://viz.tamu.edu/pub/sgi/hardware/tape/
      ftp://ion.le.ac.uk/HP_C1533A/

  Note particularly the Exabyte integration guide on viz.tamu.edu, in
  Postscript and Microsoft Word formats, which actually comes from
  Exabyte. Liam Gumley <liamg@ssec.wisc.edu>, who provided copies of
  these files, reports that they also work with IRIX 6.0.1. You may
  also find Dave Olson's scsicontrol program interesting; see

      http://reality.sgi.com/employees/olson/Olson/