> From: Mark Matlock > With the 11/83 the position of the memory board ... above the CPU uses > PMI
Yes, through the C-D interconnect; described in detail here: http://gunkies.org/wiki/CD_interconnect#Use_by_PMI The 'above' is because the CD interconnect is not a true bus, it only interconnected pairs of slots. > In the 11/84 the CPU is above the MSV11-JE memory The PMI is still on the CD connector in this machine, but the PMI is wired as a true bus on the backplane, allowing that ordering. > there are 3 Bus slots in the 11/84 above the Unibus map board, would it > be possible to put a dual width Q22 I/O board in the second memory slot > (not the PMI side of the slot) and have it able to DMA into the > MSV11-JE? It is speculated that this should be possible, but there are jumpers on the backplane you'd need to pull. See the writeup here: http://gunkies.org/wiki/PDP-11/84#QBUS_slots Noel