rickb at bensene.com
Tue Apr 15 14:08:06 CDT 2008
>I used one back in the early 70s that was pretty decent with a nice
>display. But you needed a CDC 6000-series system to run it; it was a
>real cycle hog, IIRC.
>Wonder if anyone bothered to preserve the game?
I played this a lot on weekends when I was the Cyber 73 weekend operator
This was under KRONOS rather than SCOPE. I believe that the console
command was X.CHESS
It used both CRT's, the left for a nice vector display of the game
board, and the right for a listing of the moves made thus far, elapsed
time, and for entering moves. I believe that the main program ran all
of the chess processing, and that a PPU program communicated with the
main program. The PPU took care of keeping the display updated. It
offered, IIRC, ten different levels of play. The highest level I ever
beat the machine at was level 4. Above level 4, it'd beat me quite
easily. At level 10, I had no chance at all.
The Cyber 73 had two main CPUs, and 20 PPUs (10 for each CPU). The CPUs
were essentially 6600-design, with some enhancements for certain types
of vector operations, as well as dealing with shared main memory.
The load on the machine was pretty light on the weekends, and the
operator didn't have much to do other than mount an occasional tape, or
tend to the printer. The main program did load the machine a bit, but
didn't seem to have any effect on interactive users. May have slowed
down some big (run for a few days) circuit simulation jobs, but no one
ever complained, and it was a good way to beat the boredom of sitting in
a LOUD (lots of equipment), COLD (these machines like to run in a very
cool room...even though they had their own refrigeration system for
cooling) data center.
I do recall once printing out a copy of the source. It was mostly
FORTRAN-77, but there were some sections of assembly code if I remember
correctly. I spent quite a bit of time studying the code. It was
remarkably well-documented. Someone spent a lot of time on writing this
program. The PPU code was indecipherable for me, as I never really
learned much about the PPU instruction set. Sadly, I don't have this
printout. I kept it for a while, but it ended up going to recycle
during one of my moves. Bad me.
I also wonder if there's any archive out there for it? There's a pretty
good Cyber simulator out there that I've seen. Even a fairly modest PC
today should be able to run this thing at least at "Cyber" realtime, if
not faster. The machine did take a little time at level 10 once you got
past the opening move book section of the program...machine moves would
take from 5-10 seconds, to up to 90 seconds or so, but I never made it
into level 10 deep enough to really exercise the machine hard. I think
that the level setting simply put limits on the look-ahead tree
branches. At level 10, it looked as far forward as the algorithms (and
main memory) would allow.
I also seem to recall there was some command you could put into it that
would change the left screen from the view of the chessboard, to a
"debug" view, that showed the evaluation processes involved in the
machine determining its move. It was nicely organized to show a ranked
listing of the best possible moves by its scoring algorithm, and below
that it showed a text-representation of the board, with the machine
making theoretical moves, then scoring the outcome. At the time, it was
simply amazing the computing power that this machine had.
How far we've come, and how much we've lost.
The Old Calculator Museum
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