11/45 hack?

Eric Smith spacewar at gmail.com
Sun Feb 8 16:41:04 CST 2015

On Sat, Feb 7, 2015 at 11:46 AM, Jacob Ritorto <jacob.ritorto at gmail.com> wrote:
>   I'm going to duck after asking this, but would it be at all feasible to
> rewire the main 11/45 backplane to get rid of the weird voltages in those
> bipolar slots so they'd accommodate normal boards like these?

It's not just "weird voltages". Slots 17-20 and 22-25 are Fastbus, not
Unibus, so they're not
usable for *anything* except 11/45 fastbus memory.  Slots 16 and 21,
for the Fastbus
memory controllers, do have Unibus, but I haven't verified that the
pinouts match normal
Unibus slots. They definitely are NOT wired for SPC use.

Fastbus memory could be either:

   MS11-B (MOS)
       M8110 memory control
       G401 or G401-YA MOS memory matrix

   MS11-A or -C (bipolar)
       M8120 memory control (M8110 in early versions)
       M121A-YA bipolar memory, 4K, parity
       M8111 bipolar memory, 1K
       M8111-YA  bipolar memory, 1K, parity

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