[cctalk] Re: Good computer books for 1960's computers

> Now I have to decide whether the Dnepr-1 counts as 26 bits for my list ... should parity/sign count?? Oh, and I was missing a 29-bit example ... so more checking to do (you never know, it might have imagined it!)

That's certainly a start but just the bare beginning. I suspect that, unti lthe IBM/360, most machines had word lengths not a power of two. For example, none of the DEC machines before the PDP-11. Older IBM machines had assorted word sizes; CDC and Burroughs ditto. I worked on a 1970s era Philips machine with 24 bits, and there were other minicomputer with that word length (Modcomp?). Electrologica had 27 bit words. The MC research machines had word lengths of 30 and 34 bits (the 34 bit one, ARMAC, was a successor of the 30 bit ARRA 2 with a very similar instruction set, two instructions per word, but the address space grew from 1k to 4k so the word was made 4 bits larger). ENIAC was 40 bits I think. I would count the sign since it's part of the data representation, but not the parity bit. And on Burroughs mainframes the 3 tag bits are usually not mentioned; if you do include them (sensible, since they carry semantic information) you end up with a word size of 51 bits. Not often you run into prime numbers for the word size.