On May 2, 16:29, ip500 wrote: of GR made a few cards for QBus systems. I have a GR "RX02" which has a 50-pin Shugart interface and works with ordinary 8" drives. It's a dual-height card. It's also capable of handling dual-sided "RX03" format, and I think up to 4 drives. There's an on-board bootstrap option. Plessey made (badged?) a very similar (if not identical) board. I think I have the manual somewhere. These boards were quite popular. I've seen one built into a single 8" drive case with an M8186 (11/23) and an M8047 (MXV11-A). I also have a GR DHV11, 16-channel QBus multiplexer, with channel zero mapped to the console address. It's a quad-high and needs a special 3U-high distribution box, which has (IIRC) three stacked PCBs containing a Z80 and some "stuff". Unfortunately mine is faulty :-( I don't have any docs, all I know is that it appears at addresses 160020-160036 (DHV11) and 170500-170502 (DM11 multiplexer) as well as 177560-177566 (console). According to my register dump, that is. -- Pete Peter Turnbull Network Manager University of York