Subject: Re: Internal SCSI cable length on 5000/33
To: Simon Burge <simonb@netbsd.org>
From: NetBSD Bob <nbsdbob@weedcon1.cropsci.ncsu.edu>
List: port-pmax
Date: 10/19/1999 11:46:15
> > [[ extra disks on a 5000/33 ]]
> 
> You'd probably be better off with both disks to the same connector.
> I've only had a DECstation 5000/xx for a couple of weeks and haven't
> played around with it's SCSI bus at all.
> 
> As far as the narrow SCSI that DECstations use, you should be able to
> put 7 devices plus the host on the one bus.

On my 5000/25, I used the second motherboard scsi port with a 4 inch
(10cm) cable and a PC Y power cable adapter, and that worked.  I had
to drill holes in the floppy mounting bracket to accept the HD mounting,
but that seemed to also do OK.  The alignment of the cables is a little
offcentered, so you may need to split the cable into bundles of 10 or
so wires, for flexibility.

One of the others on the list had a second internal drive connected up,
and just laid the drive into the floppy bracket, where it pretty well
stayed put without any mounting screws.

Looking at the DS5000/25 hardware manual, that second port is a real
scsi port, although the manual does not say what is supposed to be
connected there.  Perhaps they originally had a dual HD option instead
of the floppy option on that machine?

I dunno how the trace wiring on the motherboard runs, but my guess is
that it is just a short internal bus with terminators on the motherboard,
maybe.

A postscript or pdf copy of the manual for the lowend 5000 machines
is in the Linux archive in Germany, but I forget the url to it right
off (link there from the Linux DECstation links or do a DS5000
search maybe).  That is a goldmine of detailed info, and well worth
printing out (250 pages or so).  Maybe a copy needs to go into the
NetBSD archives?  If you can't find a copy, I put one on my archives
on 152.1.207.52 as maxinemanual.ps.gz.

Bob