This worked for me using an Exabyte Eliant 820...

Using ADSM Utilities, Diagnostics - record device #
   Using ADSM Command Line
        Define library 8mmlib libtype=manual
        Define drive 8mmlib drive1 device=mt2.0.0.3  (device # may vary)

        Define devclass 8mm devt=generictape library=8mmlib mountlimit=1
        Query library
        Query drive
        Query devclass

The above procedure can be found in Redbook "ADSM Server for Windows NT
Configuration and Recovery Examples" section 4.2.1 (SG24-4878-00).

        -----Original Message-----
        From:   Rod Richeson [SMTP:rricheson AT AMXINC DOT COM]
        Sent:   Friday, July 10, 1998 2:26 PM
        To:     ADSM-L AT VM.MARIST DOT EDU
        Subject:        8mm on NT

        Anyone get a 8mm defined correctly to NT ADSM?  I have a new box
and cannot
        get it to use a Exabyte 8mm.  I defined it as generictape,
because I would
        get a "no mount points availabe" as a 8mm defined drive.

        TIA

        Rod Richeson
        ADSM Certified