17 Oct
2007
17 Oct
'07
2:29 p.m.
Roger Ivie wrote:
On Wed, 17 Oct 2007, Chuck Guzis wrote:
The book "How to Design, Build & Program Your Own _Advanced_ Working Computer
System" (1981/TAB Books) has an entire chapter devoted to this, mentioning
a couple of chips.
Note the underlining (part of the title) of "Advanced" to distinguish it from
the earlier book, which was about designing, building & programming
not-so-advanced working computer systems.
I rather questioned the performance aspect too, esp. with using chips from
pocket calcs, which typically weren't too fast. It all seemed like a hardware
hacker's solution to something rather than learning some math and doing some
programming.
Fred Cisin wrote:
On 17 Oct 2007 at 12:09, Jim Battle wrote:
IIRC, it was in the .01-centennial issue of Dr. Dobb's. I have a copy of
it somewhere, but there's no way I could find it without a lot of
effort. Finally, I recall seeing an article where
somebody took a pocket
calculator chip and essentially poked simulated keystrokes at it and
then decoded the LED driver output to determine the answer. It was very
slow, though, so all it saved was the space of the floating point
library code.
I remember that one. It may have been an early issue of Byte. I
also wondered at the time if any speed was gained over just running
plain old x80 code. Well, at least it's better than using solenoids
and photocells (which
would have permitted a wider choice of calculators)
The book mentions a programming interface to calculators using relays for the
keyboard matrix and calls such a device a "compulator" (only place I've
ever
heard the expression).