SCSI adapter rumor

[matt at srs.uucp]

>> I have heard a rumour that there is an internal scsi adapter on the CPU
>> boards of machines like 3/160, 3/75's (same cpu), and all you need to make
>> scsi peripherals work with this card is a special cable that plugs into
>> the cpuboard.

Not that I know of.  Our 3/75 needs a separate card that mounts inside the
4Mb expansion board.  Note that you can mount ANY standard VME card in it
-- except for things like power consumption and heat.  We have a
Burr-Brown A/D converter in ours.

>Sun 3/160 and 3/260 machines (that I have seen, no doubt other models as well)
>can be purchased with internal SCSI tape or disk drives. When such a
>configuration is purchased, there is a SCSI controller (not on the CPU,
>but a separate board) which cannot be accessed outside the machine. Sun
>claims that you still have to buy another SCSI adaptor to attach extra
>SCSI peripherals to such a configuration; my experience suggests
>otherwise.

Indeed, when we attended a conferance in CA a few months back, Sun loaned
us a 3/260 with an internal 1/4" tape drive for demonstrating our
software.  I assumed that there would be some sort of SCSI board that I
could attach our Exabyte tape drive to.  Well, it turns out that the tape
drive hooks up to a permanently wired SCSI board via the 7th slot's P2 (?)
connector on the backplane.  A 50 pin ribbon cable runs from the SCSI
board up to the top portion of the 3/260 enclosure, where it attaches to a
SCSI to QIC adaptor board.  Fortunately for us, there was (and perhaps
always is) a 50 pin tap in the cable, presumably for attaching an internal
SCSI disk.  Our Exabyte tape drive is a Delta Microsystems unit, and
inside its little enclosure there is a (surprise!) 50 pin ribbon cable
that runs from the external connector (the standard Sun SCSI connector) to
the Exabyte guts within.  By removing the cases from the Sun and the Delta
Micro tape drive, and turning the tape drive upside down (!!), we were
able to get the tap from the Sun cable snaked up through an opening in the
top of the 3/260 far enough to hook straight to the Exabyte.  Naturally, I
wouldn't recommend this for those of you watching from home, but it worked
great (loading tapes, however, was a bit tricky, but once in, no problem).

Matt Goheen
uucp:		{rutgers,ames}!rochester!srs!matt, matt at srs.uucp 
internet:	matt%srs.uucp at harvard.harvard.edu