24 May
2011
24 May
'11
1:13 p.m.
On 05/23/2011 11:16 PM, Mike Loewen wrote:
So, I picked up a PDP-11/03 at VCF East, with a single RX01 drive.
I'm told it was used as the control processor for a VAX-11/780. It
has the following boards installed:
M7264 EB 11/03 processor with 4-Kword MOS RAM
M7940 Serial Line Unit (SLU, Async)
M7946 RX01 8" floppy disk controller
M8017 Single-line async control module
M7944 4-Kword 16-bit MOS RAM (external refresh)
M9400 YE Headers and 240-ohm terminators (18-bit bus only)
There's one open dual-width slot in the card cage. It looks like I
have the cable for the M7940 to connect to a terminal, as well as the
RX01 cable.
With 8KW of RAM, what would I be able to run on this system?
Recommendations? I'm a novice in the PDP-11 world.
Yep the 780s used a LSI11 as a boot diagnostic processor. It was there
to copy the microcode into ram.
The 780 had a minimal microcode in rom but the major part was soft
loaded. When diagnostics were needed
the LSI 11 could load alternate microcode for that and I believe do some
system monitoring.
With 8KW you need a really old copy of RT11 maybe V3 or V2 and it would
not do much. However finding
another 8KB or even a 32KW ram board is not that hard and then any
version is runnable. the minimum
for a runnable system is 16KB if memory serves. With a single 32KW you
actually get 26KW of ram
and the rest is mapped out for IO.
Allison