From the its been way too long to remember
department...
 I just put an old HP SCSI 9-track tape drive on my 4000/400 running
 Vax/VMS 5.2... Does VMS probe SCSI devices at boot time?  Is there a
 way to access this drive without re-generating the system..? 
What happens when you do a 'SHO DEV MK'?  For example:
$ sho dev mk
Device                  Device           Error    Volume         Free  Trans
Mnt
 Name                   Status           Count     Label        Blocks Count
Cnt
MONK$MKA500:            Online               0
$
Though the above is a on a PWS 433au running OpenVMS 7.2-1H1 and the drive
is a DEC TLZ06 (4mm DAT).
                Zane