uVAX II + KFQSA + DSSI Drive and the last touch?

From: Chuck McManis <cmcmanis_at_mcmanis.com>
Date: Sat Feb 16 16:22:11 2002

At 12:38 AM 2/16/02 -0500, Gunther Schadow wrote:
>I just came home and there my new KFQSA card I got on eBay was
>in the mail..

Great fun

>I don't know much about DSSI however and I'm not sure I have
>all the pieces I need. I have a KFQSA, a 50-60 pin cable,
>round and two connectors each side, then a bus cable, same
>number of pins to be connected to that round cable and 3
>connectors, apparently for three drives. Good. But at the
>end of that cable is a male connector with about half as
>many pins. What is that for, please don't say it's a terminator,

You have the 'innards' of the MicroVAX 3800/3900. The KFQSA connects to the
round cable it routes up through the BA213 then plugs on to the longer
cable which plugs into the three drives installed in the BA213 and then
exits on the left where you put, yes, the terminator.

The only thing you are missing is the drive bulkhead that lets you tell the
drive what Unit number it should appear as.

>where the heck would I get such a terminator from?

Someone on the port-vax list ? :-)

>Could I
>just connect the round cable directly to one DSSI drive without
>that bus cable, such that I would not need that terminator?

No. However, I've run DSSI drives that did not have termination and while
it did cause more retries than normal, it was ok for short term use. Send
me your address off list and I'll see if I can find a terminator for you.

>Then there are some DIP switches on the card, what are they
>for?

You will need to search in the archives, and this is where you will have
some problems.
The KFQSA is a "smart" board. It can appear as 1, 2, 3, or even 6
MSCP/TMSCP controllers on the Qbus. Further, the drives themselves are
"smart" in that they talk to the controller like they are little HSC units.
All architecturally complete but someone complicated for simple setups.

There is a combination of the switches that will force the KFQSA to control
one drive and be one MSCP controller and whatever the drive thinks still
call it unit 0.

>And of course the drives have front panels and I have three
>drives and just one front panel. How essential is that front
>panel?

It comes in handy but you can run without it.

>Has anyone ever installed DSSI in a uVAX-II with the small
>cabinet? It's pretty tight in there. How about this: right
>now there is that cable for the RQDX3 that goes into the
>front part of the box and apparently is spliced there to
>connect to the MFM drive and the RX33/50 (?) floppy drive.
>What if I throw all this stuff out and use that flat cable
>to route the KFQSA into the front and hook up the DSSI
>drive where I have the MFM drive now and put in a TK50
>where the RX50 is now. Anyone ever done that?

I believe Megan Gentry has a setup like that. The issue is that there is no
provision on the DSSI drive itself to be terminated so you need to have
another connector coming off the drive to hang the terminator on. An
alternative you might consider is having the drive mount in an external
5.25" drive box and run the flat cable out to it. It wouldn't look very
pretty but you could put the terminator on it that way.


>I must also say I really appreciate the VAXBI and XMI busses
>with their zero-insertion force and their clean way of
>connecting peripherals all to the backplane instead of
>just anywhere in the front. The way these Q-BUS and UNIBUS cards
>are jammed into their slots with all the cables squeezed
>between those cards, and the cards all bent to make room for
>the cables and connectors is not beautiful, if not frightening.
>Isn't that terribly rough on the hardware?

Generally, yes. Sometimes you can get a crack in a PCB trace that is only
an open circuit when the board is flexed *just* the right way.

I think you'll be happier with a BA213 but it should be possible to do what
you want to do.

--Chuck
Received on Sat Feb 16 2002 - 16:22:11 GMT