Subject: SCSI drives and Sun 3/50's...
To: None <>
From: Gordon W. Ross <>
List: port-sun3
Date: 11/21/1995 13:02:41
> Date: Tue, 21 Nov 1995 09:46:12 -0600
> From: Greg Oster <>

> Hi all....
> I recently picked up a Sun 3/50 for the sole purpose of playing with
> NetBSD.  At present the machine has no hard drive, and I don't have
> an ethernet card in my other machine (Amiga 3000, running NetBSD),
> so needless to say I'm probably going to have some fun getting this
> thing to boot.  After having read the Sun Hardware FAQ, parts of the
> SCSI FAQ, and nearly all of the previous posts to port-sun3, here
> are some of the problems I'm having:
> 1) I pulled down the boot tapes and what not, and put them on a
> tape, (my tape drive is a WangTek 5150ES).  When I connect the tape
> drive to the 3/50, a power-on of the tape drive results in it's
> light staying on, and when I insert a tape it doesn't automatically
> rewind it.  (It does the same thing if I turn the drive on with the
> 3/50 on or off).  As far as I know all termination is correct.  If I
> mask out one of the pins on the Centronics connection (I'm pretty
> sure it's not pin 25 or 26 though) then the drive will behave
> properly (i.e. light blinks on power up, and will rewind when tape
> is inserted) but the 3/50 still doesn't want to [...]boot from it.

Many (most?) older Sun machines do not provide termination power.
Worse, many of them have the TPWR pin CONNECTED TO GROUND!  I have
turned at least one diode into a "fry-ode" thanks to this little
wiring error on an old Sun3/50 (Grumble!)

The easiest solution is to use non-standard cabling inside the
SCSI case directly connected to the Sun.  Find the middle two
conductors (pins 25, 26) on the ribbon cable on the connector
where the cable from the Sun is attached, and cut them.  (Only
26 needs to be cut, but 25 is a non-connect anyway, so I just
do both of them so I can count from either side of the cable.)
Mark that connector "Sun host" on the ouside.

You will then need to arrange for some device on the "far" side
of the cut to provide termination power (i.e. the last device).

> (On a related note, I've got an old Panasonic WORM drive in a
> case which I'd like to use as an external case.  But when I hook up
> the drive (3/50 off), and power up the drive, the light on the drive
> doesn't "blink" once on power up.  If I mask out the same pin as
> above, then it blinks properly :-( ).  Is there any chance that I
> can boot the 3/50 with the 5150ES? (I tried disabling parity on the
> 5150ES, but that didn't help either :-( ) If I get the 3/50 going,
> will I be able to use the 5150ES from NetBSD?  Any ideas as to
> what's wrong (if anything) with the SCSI connections?

Some older PROM revisions may not want to talk to the 5150.
(Failure is "DMA never completed" or something like that.)

> 2) I've got a couple of drives in my A3000 that I could "borrow" to
> try and get the 3/50 going.  One is a Quantum 105, and the other a
> Maxtor 7213 (213MB) (both SCSI, of course).  Will either of these
> work, and/or do I need a special external case?  I'd take them out
> and give them a try, but I don't want to do anything till I have a
> good idea that they will actually work... (i.e. I'm actually *using*
> them right now, and removing them would be a fair bit of work..)
> Would it be better to try and dig up an old drive known to work with
> the 3/50? (e.g. an old WREN or something?)

Almost any SCSI disk should be fine, and most tape drives will work
if you have an up-to-date PROM.  (What does it say at power on?)

> 3) Assuming one of the drives in 2) works, will a "dd" be sufficient
> to install a sun-compatible disk label/root partition on the drive?
> (I'm not sure how I'll get the root partition on the drive, but that
> should be a minor detail).

There is no easy way to do that.  I'd concentrate on tape boot.
(That way gives you a recovery path if things "blow up" 8^)