Talk:CASINO

Medidata's previous name

According to Special Follow-up Feature: Nuclear Family:

Scientific Engineering Institute. The SEI was .. eventually rebranded as Searle Medidata Inc., a subsidiary of G.D. Searle.

So if the Bell quotation from Computer Engineering:

DEC also never built a PDP-3, although one was designed on paper as a 36-bit machine. [...] In 1960 a customer (Scientific Engineering Institute, Waltham, Massachusetts) built a PDP-3

is correct, this seems to be the machine he was talking about. Which fits with things in the letter from Rawson to Lane, which speaks of:

the basic 4K memory. This memory consists of two PDP-1 memories placed on top of one another to provide 38-bit words

At first I was thinking 'if the PDP-1 was 18 bits plus a parity bit, making its memories 19 bits wide, that would check - if CASINO was 36 bits, plus a parity bit - or a parity bit for each half-word, if the machine was prepared to do half-word writes (the way PDP-11 memories have separate parity bits for each half-word, because they can do byte writes)'. If the PDP-1 had parity, that would all check, and explain why the paired PDP-1 memories were 38 bits wide - but I decided I should check to make sure the PDP-1 had parity. It didn't! But, in the PDP-1 Maintenance Manual (pg. 8-7, 214 of the PDF), I found:

The core bark actually includes an extra core plane which is completely wired in. .. The extra 19th plane is not ordinarily used, but is provided in case it is wanted for some special application

So either CASINO had 36 bit words, with parity (or it had no parity :), or 38 bit words... But still, I'm fairly certain this was the 'PDP-3'. I will leave the PDP-2 and PDP-3 articles as they are, for the moment, but if you think I have correctly identified it, I will fix them. Jnc (talk) 01:48, 8 January 2024 (CET)