15 Jan
2014
15 Jan
'14
11:18 p.m.
On Wed, Jan 15, 2014 at 6:37 AM, Bob Vines <bobvines00 at gmail.com> wrote:
The MM8-AA & MM8-AB Engineering Specification at
http://www.pdp8online.com/pdp8cgi/query_docs/tifftopdf.pl/pdp8prints/mm8aa.…
shows that your jumpers are in locations 1-3 & 3-4. It then states
that those two jumpers, in combination, will configure the module for
memory locations 32K-48K, which it then states are "presently not
available." But it was written in 1975. However, the 1978 KT8-A
Memory Management Control (EK-KT08A-UG-001 at
http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/pdp8/pdp8a/EK-KT08A-UG…)
allows an -8/A to use up to 128K of any -8/A memory type. Perhaps the
previous user of the MM8-AB module had the KT8-A module to allow the
use of more than 32K?
I have a KT8A and I've used it with MOS memory, but never with core.
I do see that the photo of the MM8 has signals on the "E" finger,
which means it ought to work in a system that has over 32K. It would
be interesting to calculate the original sale price of a box with a
KT8A and stuffed with as much core as it could be. I'll bet it's a
scary number.
-ethan