Synergy User Manual and Tutorial. - THE CORE MEMORY

Synergy User Manual and Tutorial
The picture on
the left shows
Williams and
Kilburn at the
console of the
Manchester
Mark I. It was
built in 1949
and could
store data in
addressable
"line"s,
holding one
40-bit number
or two 20-bit
instruction
registers, and
had two 20-bit
address modifier registers, called "B-lines" (for modifying addresses in instructions),
which functioned either as index registers or as base address registers. This Mark I was
of historical significance because it is the first machine to include this index/base register
in its architecture, which was a very important improvement. It was the first Random
Access Memory computer. It could perform serial 40-bit arithmetic, with hardware add,
subtract and multiply (with an 80-bit
double-length accumulator) and logical
instructions. The average instruction
time was 1.8 milliseconds (about 550
additions per second), with
multiplication taking much longer. It
had a single-address format order code
with about 30 function codes. The
machine used two Williams tubes for
its 128 words of memory. Each tube
contained 64 rows with 40 points (bits)
per row, which was two “page”s (A
page was an array of 32 by 40 points).
It also had a 128 page capacity drumbacking
store, 2 pages per track, about
30 milliseconds revolution time on 2
drums (each drum could hold up to 32
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