On Sep 15, 0:46, Patrick Finnegan wrote: and 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. 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. 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