On 5/16/25 20:26, Henry Bent via cctalk wrote:
On Fri, 16 May 2025 at 20:33, Jonathan Stone via
cctalk <
cctalk(a)classiccmp.org> wrote:
However a pure Q22/Q22 backplane will not support
any Microvax II or III
memory cards, as they use CD slots as part of the Private Memory
Interconnect (PMI) to the CPU. You could run a KA630 with just the 1MB on
the CPU board; but it'd be even more constrained than a microvax
2000/vaxstation 2000 with just the 2MB onboard memory.
Does anyone know what the reasoning behind the 1MB on the KA630 board was?
Just enough for a realtime application, maybe, or a single tinkerer? I
can't see running much of anything serious in 1MB on a uVAX II in 1985 if
you were really trying to take advantage of the hardware, so I wonder if
the idea was that the board would have other applications.
MicroVMS on the uVAX II was a demand-paged virtual memory
system, and ran QUITE a lot of stuff in the basic 1 MB. The
original aim of the uVAX II was to support a single user
desktop environment, and it did so VERY well. If you wanted
to surf the web with streaming videos, then it was
overwhelmed, but nobody was doing that in 1986 when it came out.
I ran a home system starting in 1986 on a uVAX II with just
the on-board memory, and it ran FINE like that. I did a lot
of tape duplicating as a DECUS librarian, and also ran a
home environment monitor as a permanent batch job. I
started with just the console terminal, then added a DHV-11
serial multiplexer, then a VCB01 monochrome graphics board
and DECWindows, then upgraded to a VCB02 and added a few
more MB of memory. I also did driver developement on that
system.
Jon