From: Morton Goldberg Date: 2007-07-20T13:34:14+09:00 Subject: Re: Taking the bull by its horns [was background] On Jul 19, 2007, at 9:00 PM, John W. Kennedy wrote: > Never had a 650 to work on, but read the manual once, a long, long, > long time ago. My first programs were written for the 7070, which > was the follow-on to the 650, but, since it used core, had a > conventional instruction counter instead of a next-instruction- > address field. I wouldn't characterize any 70X/70X0 machine as a follow-on to the 650. They were a mainframe series derived from the Whirlwind project, an IBM military contract. The R&D tab for the 70Xs was picked-up by the US taxpayer. The 70Xs were vacuum tube machines and were introduced at the same time as the 650 -- the 70X0s were the later transistorized versions. I don't remember a 707, but if there was a 7070, I would expect a 707 existed as a predecessor. I did some Fortran programming on a 709 and a 7040. AFAIK, the 650 was developed as a business machine with IBM's own funds by an entirely different engineering group than the Whirlwind group. There is nothing in common between the two architectures. The 650 not only used dual-address instructions, it wasn't even a binary machine. It was a dead-end architecture. Regards, Morton