11 Oct
2014
11 Oct
'14
1:55 a.m.
On Fri, 10 Oct 2014, Engel, Michael wrote:
I think (and this is going back to the early 80s) that some WICAT models
did. I've used the 150, 160, and 200, but never saw a 220. The smaller
models were Multibus, and the 200 on had something loosely based on it and
was unofficially referred to as the Pussy-bus. The P2 bus on those small
ones was used for something that I've long since forgotten; there was a
project in the Lionel Singer Group (Aussie agent for WICAT) to use
standard Multibus cards in them until we discovered upon reading the
circuits (we had circuit diagrams in those days!) that WICAT had hijacked
the P2 bus, possibly for extended memory, possibly for its weird ICI board
(8-port serial board + disk, as I vaguely recall), possibly something
else.
I was glad to see the end of the WICATs, because their attempt at System
III was woeful; I had to do pre-sales demos, *knowing* that the damned
thing would crash on me, and got very good at excuses. "Sorry guys, we've
been having a bit of trouble with this new controller, but we're told
it'll be fixed Real Soon Now(tm)" when I knew that it was the poxy OS at
fault. How do you explain to the customer that the OS itself is
fundamentally rat-shit?
I am desperately trying to forget the exact details, but it involved
someone telling Lionel Singer himself that his half-arsed idea was just
that...
The P2 bus is
designated as "private" i.e. do whatever you want with
it with your proprietary hardware. I don't think the "standard" CPU
board even looks at it.
That's what I also thought. Do you know if there were systems which used
P2 to connect to memory boards? [...]
The terminal emulator (screen and minicom behave identically) receives
the output from the console perfectly - otherwise, I would have also
suspected an incorrect baudrate. And different baudrates for RX and TX
would be highly unusual (I have only seen these in German BTX dialup
systems in the 1980s, which used 1200/75 baud modems).
1200/75? That was popular in Australia, on a scheme called Viatel, which
thankfully died off when ISPs began to rise up (until then it was either
FidoNet or the Phone Company's Viatel) and implement 1200/1200.
The
serial cable is working, we tried all sorts of handshake
configurations. If we get any characters back (the system is running
at 9600 baud, I tried all combinations of 7/8 bit,
none/even/odd/mark/space parity and 1/2 stop bits), these are garbled
and contain mostly "1" bits (0xfc, 0xfe, 0xff or similar).
Have you tried speeds other than 9600? They look to me like framing
errors. Luckily, the driver chip for the UART RX line is an
AM26LS32. While this
chip is no longer available, I can get an AM26LS32A here at Farnell
(which is just around the corner from my house :-)). Does anyone know
the difference between the 26LS32 and the 26LS32A? I only found a page
at TI that didn't list specific differences...
Offhand no, but Farknell (as they're known in Australia - say it out loud)
ought to know, as they're pretty clued up.
-- Dave