Derek Peschel wrote:
STC = Stantec = Standard Telephone and Cable. They
sold a truly strange
computer called the ZEBRA. It was designed to be cheap (it used a drum
for storage and did arithmetic serially).
The instruction format is unusual -- 15 function bits (I think each affects
a gate) and a 12-bit address of a drum location and a 5-bit address of a
"fast store" location (basically a small number of registers). The amount
of logic in the machine is small, so the instruction decoding is simple
in a sense. But the logic is connected in very subtle ways -- two things
can happen independently, or an instruction can set a whole sequence
of events in motion.
There is an emulator for this machine; I have some of the literature
about it too. But I don't have the manual or the schematics, and the
literature I have just doesn't make the design "click" into place
in my head. The emulator code is not very intuitive either. So that's
why I'm hoping someone else has heard of this machine.
-- Derek
... Stantec Zebra, was developed from a hypothetical machine devised by
Dr. W. L. van der Poel of the Nteherlands Post Office. The original
Zebra was a medium sized scientific computer with drum store and valve
circuits.
Zebra stands for : Zeer Eenvoudige Binaire Reken Automat
or Very Simple Binary Calculating Machine
I snagged a set of manuals and marketing literature about the beastie as
follows:
1 Some Advantages of Zebra Programming 9 pages
2 A Brief Outline of what Stantec has
done and is doing - March 1959 21 pages
3 Stantec Zebra
Electronic Digital Computer 7 pages
{marketing lit)
4 An Introduction to Stantec Zebra 13 pages
5 Notes on the Stantec Computing System 4 pages
6 A Outline of the Functional Design
of the Stantec Zebra Computer 42 pages
7 Stantec Computing Systems 16 pages
{marketing glossy}
8 Applications of Zebra ~50 pages
{marketing papers}
I think you want 4 and 6. I'll see about scanning them (and the others)
for you.
-- hbp