Netcom system with an HV-1148 backplane

Ok. Apologies for not being thorough with my description. The backplane is an 8x4. The diagram on the card cage is as follows: Remeber that this is a flip cardcage on hinges, so in fact when put back in the box everything ends up as it should. Modules are inserted upside down, right to left, bottom to top... ------------------------------------------------------------------------- MODULE VIEW D C B A Priority Chain -> 8 ---- ---- ---- ---- ---> Lowest | - - 7 ---- ---- ---- ---- <- -> 6 ---- ---- ---- ---- --| | - - 5 ---- ---- ---- ---- <- -> 4 ---- ---- ---- ---- --| | - - 3 ---- ---- ---- ---- <- -> 2 ---- ---- ---- ---- --| | - - 1 ---- ---- ---- ---- <--- Highest THE PRIORITY CHAIN SKIPS SLOTS 2CD and 3CD, WHICH ARE NOT NORMAL LSI-11 BUS ------------------------------------------------------------------------- Ok, now 1A and 1B are preprinted CPU. 2D marked RL01 2C marked M8013. 3D marked RL01, 3C marked M8014.. CPU goes in higest slot 1AB. As it should. Slots 2 and 3 are oviously different. Since they were meant for the 2 quad board RL01 controller RLV11 that makes sense. On to the next question: This were the boards in the system and where they were installed. I am assuming that's how the previous owner had them installed when he had the system running with RT11. I just don't see how it could have worked. 1AB - M8186 11/23 CPU (don't know if it's a YA B or C, but definitely no FP going from memory two chips on it, CPU and MMU?, a rev D board) 1CD - Third party 256Kb (with 128K installed) parity memory board. 2CD - M7940 DLV11 (don't know if it's a YA C D or E) 2AB - MicroTechnology MXV22 RX02 compatible disk controller 3ABCD - M8012-YA BDV11 All cards duals except for for the M8012 which is a quad. I can sort of see how the M8012 would work in slot 3 (it does match the ABCD in the chain, and it is a slot that is different), but if slot 2 is also different, the M7940 could not have worked. It's an AB card, stuck in a CD slot. I still have to figure out the 18vs22 bit issue. And correct me if I'm wrong, but unless I have an even number of dual cards, a quad card will not work in the system (leaves a 1/2 slot empty before it). If I was to go with an RLV12 controller that's a single quad board in Slot2, I don't think that I can leave slot 3 empty. Now, if it was a 22 bit backplane I could stick TWO RLV12's in there, and that would make it all ok. Speaking of... Anyone have a spare RLV11 set or an RLV12 they would be willing to part with? And thanks for the correction on the extended address lines... -- alex