On Sep 15, 0:46, Patrick Finnegan wrote:
> I've got a PDP-11/23 cpu, M8044 32kW memory card, DLV11-J serial card,
and
> an RQDX1 set up, and starting up into ODT. I've got an ST225 'MFM'
> interface drive and an RX50 I'd like to hook up, but no cab kit for the
> RQDX1.
>
> Four questions:
>
> 1a) Does anyone have a pinout for a cable that'll let me hook up the RX50
> and MFM drive to the RQDX1
I have two documents that might help. Years ago, I made two (different)
"distribution boards" so I could use my RQDX1 and RQDX3 on machines that
didn't have the proper DEC board. One was no more than a small (2" x 4")
perfboard with a 50-way connector for the cable to the RQDX1, a 34-way
header for the RX50, and another 34-way, with adjacent 20-way headers, for
one or two RDxx drives (actually I used either a Rodime or a Seagate). It
also had a terminator pack (7-resistor SIL pack) and a set of jumper pins
to take the place of the panel pushbuttons. The interconnections were just
hand-soldered, using wire-wrap wire.
However, I also made a PCB which does the job more neatly, and which I
mounted inside an old TK50Z box (is that a "leprechaun box"?), along with
the original PSU, an RX50 (where the TK50 used to be) and a Rodime 10MB
drive. It's still in use today (literally today, as I'm using it to copy
some RT-11 stuff for someone).
I've put the document I wrote (in PostScript format) listing the RQDX
distribution board connections and signals, along with some notes about
using random floppy drives, on my web site. It's not just a list of
signals and pin numbers; it also describes what they actually do. I've
also put the layout for the distribution board PCB up there.
http://www.dunnington.u-net.com/public/RQDX/
I once traced out the connections and drew the circuit diagram of a real
M9058 distribution board (which is what my PCB emulates) but I can't find
the document. Sorry! However, I do remember that it's very simple.
> 1b) What DIP switch settings should I use on the RQDX1?
Well, that's easy, because it has no switches :-)
If you mean the jumpers, they're set as follows:
There's a group of jumpers to set the starting LUN (Logical Unit Number) of
the RQDX1, at the back edge on the right (top left if you're looking at a
board from above, with the contact fingers downwards and the LEDs and
connector at the top). The jumper positions are labelled 0 to 7, and
represent powers of two, so no jumpers at all sets "0", a jumper on the
first position ('0') sets "1", a jumper on the second and third positions
sets "6", etc. If this is the first or only MSCP disk controller in the
system, set LUN 0 (which means it controls drive units 0-3, ie four LUNs
starting at 0) ie remove all the jumpers.
Another set of jumpers, near the "Row B" contact fingers, sets the
addresses of the IP and SA registers, by setting A2...A12. The A2 jumper
position is nearest the "Row A" fingers and the A12 position is near the
"Row C" fingers. Jumper IN is a '1', no jumper is a '0'. A0 and A1 are
always zero, and the higher bits are controlled by BBS7 so there are no
jumpers for those bits.
The standard address is 17772150, set by jumpering A3, A5, A6, A10, A12.
The interrupt vector is set by software as part of the bootstrap; it's
usually 154 for the first MSCP device.
Finally, there are four wire links, W1/W2 near the "Row C" fingers and
W3/W4 near the centre of the board. Actually, they're usually zero-ohm
resistors. W1 and W2 are for grant continuity, they are IN for use in Q/Q
or Q22/Q22 (serpentine) backplanes and OUT (removed) for use in Q/CD or
Q22/C (straight) backplanes. I don't know what W3 and W4 do, but they're
IN on mine.
> 1c) Does someone have a bootstrap I can enter using ODT to boot RT-11 off
> of an RX50 or the hard drive on the RQDX1?
That's harder. The way MSCP works, by setting up message blocks and
passing them to the controller, makes it a bit complicated, and I've never
seen a stand-alone bootstrap. The easiest way might be to get the boot
code off an Emulex controller to disassemble, as at least that wouldn't
have all the overhead of dialogs and options for other devices which the
DEC boot ROMs have.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Sun Sep 15 2002 - 10:19:00 BST