15 Feb
2025
15 Feb
'25
2:47 p.m.
On Sat, 2025-02-15 at 12:53 -0700, ben via cctalk wrote:
Around what time did core memory drop in price that
one had ample
main
memory to compile with? I am guessing the late 60's.
The IBM 704, first delivered in 1956, had 8,192 words of 36-bit core
memory.
The IBM 701, developed in in 1951 and delivered in 1953, had memory
consisting of 72 Williams Tube CRTs; some were later converted to core.
Like SWAC, there was a tendency of zero bits to leak into adjacent
words, so every ten milliseconds or so, programs would swap CRT memory
to drum and back.
The first IBM 1401 was announced in October 1959 and delivered shortly
thereafter, with 4k characters of of 12.5 microsecond core memory. One
could eventually get 1401, 1440, and 1460 with 16k memory. 1410, and
the faster but functionally identical 7010, could be gotten with 100k
memory.