On Jan 4, 13:35, Ethan Dicks wrote: It Two other things occur to me. The first is that memories like the MSV11-D (M8044) and MSV11-L (M8059) have jumpers to enable or disable memory that corresponds to the I/O page. This gets a little complicated... Most DEC memories decode the BBS7 signal to sense access to the I/O page and disable memory access accordingly. The MSV11-D has a jumper 1-2 to enable memory in the lower 2KW of the I/O page for systems that don't use the whole I/O space; jumper 2-3 (the factory setting) to disable memory in the whole top 4KW. The MSV11-L has a similar arangement, using jumpers 28-29 to enable the memory in the bottom half of the I/O page, and 27-28 to disable it. And that's the second thing. The MSV11-L doesn't use BBS7 for everything it decodes, so you have to set it according to whether it's in a 22-bit system or an 18-bit system. If there's a jumper from R-T, it's set for a 2MW system. Remove it for 128KW systems. It's also a parity memory, unlike the MSV11-D, and furthermore it has it's own on-board parity control and reporting register. I don't think that would stop it working if not set up, though. If you want to check the parity jumper settings, the factory default is 9-10 out, 10-11 in, 18-19 out and 19-20 in (to enable parity); 1-2 in and 2-3 out (to enable register reporting); 6-7 in and 7-8 out (necessary to disable wrong-parity writing which is used for testing); F-H in and J-H out (to enable the CSR for parity setting/reporting rather than other methods). There are also jumpers to enable/disable half the board. Normal settings are 32-33 out and 33-34 in for a fully-populated board (reverse for half-populated) and 15-16 in and 16-17 out (the reverse disables the lower bank, used if part of the bank fails). Most of the remaining jumpers set the starting address. For a starting address of zero, you want pins P,N,M,L disconnected, and pins V,W,X,Y,Z disconnected (the addressing is done in two parts). To change the address to something other than zero, you would connect one or more of these pins to pin K (ground). it Quick check is to hold the board with handles at the top/contacts at the bottom, and look for a metal jumper (W18) about an inch below the handles, about halfway between them, and above a diode jumpered with a red wire. If it's there, it's a Rev.A. Q22 I've done it too. A standard BDV11 doesn't terminate the upper 4 address lines, but there's an ECO (ECO 005?) to fix that. It consists of adding 4 short wires from the contact fingers to termination resistors that are otherwise unused. -- Pete Peter Turnbull Network Manager University of York