guy@rlgvax.UUCP (05/12/84)
> The description referred to as a description of STRETCH sounded more like > a description of the IBM 7080 commercial processor...a very fast, expensive > implementation more like the 1401/1410 than the 1620. Stretch was the 7030. > For details, see Bucholz's book "Design of a Computer System". A lot of > good ideas from Stretch appeared later in the /360 line (and a lot of good > ideas didn't). If you're referring to > The IBM STRETCH (7030) ca 1957, was bit addressable. The instruction > contained a word address (64 bit word) , bit offset, and a "byte length", > or operand size. The machine was a masterpiece of baroque architecture: > all sorts of nifty things that were practical to use only in assembler. > The term "byte" was coined for the STRETCH, and originally ment a variable > size operand. the STRETCH did look like that. It even had, if I remember correctly, BCD add and subtract instructions. It was, however, *primarily* a binary, single-accumulator, architecture. It had a 64-bit word, but fixed-point arithmetic was done on bit fields of arbitrary length starting on an arbitrary bit boundary (it was a fully *bit*-addressible machine) and was done an eight- bit *byte* at a time; floating point arithmetic (which was supposed to be quite fast for the time) dealt with 64-bit floating point numbers (possibly 32-bit also, I don't remember) and was a good deal faster than fixed-point arithmetic. It did not, however, resemble the 14xx series or the 1620 very much. It *did* have one of the more interesting ideas for a multi-user system. Since a lot of programming at the time was done on a single-user system using the control panel (lights, switches, corsets, bustles - sorry, got carried away a bit there :-)), they decided that the right way to do a multi-programming system was to have the front panel be purely an I/O device and have the driver for it permit a user to manipulate their process using this software-driven control panel! I have no idea whether the ultimate OS for this beast actually did this or not. Guy Harris {seismo,ihnp4,allegra}!rlgvax!guy