8 Feb
2012
8 Feb
'12
4:08 p.m.
On 02/08/2012 10:23 AM, Ethan Dicks wrote:
The uVAX-I has a dual-board CPU that must be installed
in slots 1-2 of
a backplane with CD slots, and the memory sits _on_ the Qbus, so with
22 address bits, you top out at 4MB. The later MicroVAXen fit on a
single board and use PMI memory (different boards, matched to the type
of CPU). I don't know the MicroVAX III memory max off the top of my
head (after my time), but the uVAX-II has 1MB on-board and can take,
IIRC, 12MB in the first two slots.
The MicroVAX-II maxes out at 16MB. The onboard memory adds to
whatever you put in the second and third slots, but if you put two 8MB
boards (or a third-party 16MB board, DEC didn't make one but I think
Chrislin did, and perhaps Dataram) the onboard 1MB is disabled. That's
why we see MicroVAX-IIs with odd amounts of memory like 5MB, 9MB, 13MB,
but maxed-out ones have 16MB.
-Dave
--
Dave McGuire
New Kensington, PA