PDP-11/84 Qbus slots for memory

[Noel Chiappa]

    > 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