Trying to get running an LSI 11/23

From: Ethan Dicks <ethan.dicks_at_gmail.com>
Date: Thu Dec 30 00:12:42 2004

On Tue, 28 Dec 2004 11:25:31 -0800 (PST), Vintage Computer Festival
<vcf_at_siconic.com> wrote:
> > > 3. The Data Systems Design card has "DY:" written on the handle.
> >
> > DY: is the normal device name for an RX02 8" floppy. Does this card have
> > a 50 pin header on it? If so, you might have got one of the cards that
> > does the RX02 format on normal (SA800-series) drives, which is just what you
> > want, I think.

I have one of those attached to a Shugart SA-800-series drive from a
Dataram-branded Qbus enclosure. It is _not_ a DSD-brand card.
_Might_ be Dataram, might be some other vendor. One nice feature is
that it's possible with this particular card to turn a bulk-erased
disk into a formatted RX01 disk, but I'm not sure I have the
instructions around anymore (the last time I did it, it was 1985 or
so).

In general, though, no matter what the drives a 3rd-party card can
talk to, they all are presented as either an RX11/RXV11 (RX01) or
RX211(?)/RXV21 (RX02) interface, down to the register level, so
ordinary boot ROMs and device drivers work with them.

> No, this has just a single 28-pin (dual row header) connector. I don't
> recall ever seeing a disk drive with a single 28-conductor ribbon cable.

The DSD stuff had odd cables, and that sounds about right. The DSD
enclosure you are looking for will have one or more boards in it, and
one or two SA-800-type drives inside. The boards _might_ be Z-80
based, but that also might only be the particular model I happen to
have at home. There are several models of DSD drive enclosures.

> > > The system powers up. There are +5V and +12V LEDs on the front of the
> > > panel that come on, and I've checked these lines at the power supply and
> > > they are good. One oddity: the terminal marked -12V is a perfect -0.00 on
> > > my volt meter. WTF?

I remember during our COMBOARD development that we had to drop on a
charge-pump to our board because some Qbus enclosures did not provide
-12V. You could look up the bus spec and fire that up from an
external source if you need it. I'm not sure if the DLV11J in
particular has to have -12V supplied (check its prints or perhaps a
DEC configuratiion guide), but _our_ board did. I still have a slab
of encapsulated charge pumps... ISTR we paid $17 each for them 20+
years ago. They are self-contained, 4-pin devices, about 2-3mm thick,
perhaps 20mm x 30mm? Pretty much +5V and GND in, -12V out with
enough current to run two sync serial ports buffered with 1488/1489
drivers/receivers. Fortunately we had plenty of room to stick the
charge pump dingus on a corner of the board.

-ethan
Received on Thu Dec 30 2004 - 00:12:42 GMT