21 Mar
2020
21 Mar
'20
4:19 p.m.
Johnny Billquist <bqt at softjar.se> wrote:
I think the 11/53 commonly ran at 15 MHz, while the 11/73 could be found
with 18 MHz. But otherwise yes, same basic system, really.
Not a speed demon. Upgrading to an 11/83 does make a noticeable difference.
The big win for the 11/83 was the PMI bus, not the clock speed. That's entirely
different hardware, though, and not much I can do about that. PMI memory wouldn't be
a problem in the BA123, but I don't believe there was ever an 11/83 board made with
S-box handles. Actually, I think the 11/53 and 53+ were the only S-Box PDP-11s made (at
least they're the only ones I remember).
The M8190-AB (I think) 11/73 board was 15MHz and the M8190-AE 11/73 was 18MHz. And
you're right - the 11/53 was 15MHz. Again, I don't think DEC ever made a 18Mhz
11/53.
Bob