27 Jul
2001
27 Jul
'01
12:45 p.m.
At 09:26 AM 7/27/01 -0400, John wrote:
Its a bus issue, in the 4000/300 and beyond DEC went to a dedicated bus for
the CPU and memory that was _not_ Q-Bus. Thus in those machines the
backplane as several slots of this other bus (CPU + memory) and then a
regular Q/CD backplane to the left of those. One big Sbox bulkhead covers
the weird slots (I call it the CPU box)
If you replace the backplane in a B400X then you can use a
4000/{3,4,5,6,7}0{0,5}{,a}
--Chuck
So you can
plug a 3400 card set into it, or a KA660 (VAX 4000/200)
card set into it. Both work just fine. But you _cannot_ plug a 4000/300
board set into it.
Is this a Q-CD issue, a bandwidth issue or what?