[email protected] (Anne & Lynn Wheeler) writes: > http://people.cs.clemson.edu/~mark/acs_end.html
re: http://www.garlic.com/~lynn/2013d.html#19 Query for Destination z article -- mainframes back to the future end of above article has two "sidebars" ... one on multithreading and the other that some of the features from acs-360 (from the late 60s) show up for the es/9000 in the early 90s. i've pontificated before about getting sucked into participating some in the mid-70s on multithreaded design for the 370/195 (that never got announced). the 370/195 case was that conditional branches drained the pipeline (branch throughput problems also discussed in the acs-360 article) ... and most codes would only achieve about half 370/195 throughput (because of the pipeline drain, conditional branches also discussed in the acs-360 article) ... having two independent instruction streams (each running at half 370/195 thruoughput) had chance of keeping execution units operating at full capacity. other from acs-360 article: over a three-month period, Amdahl convinces Earle that a S/360 version of ACS will be faster than the ACS-1; Amdahl and Earle sketch out a design that has 2/3 the cycle time of ACS-1 (8 nsec vs. 12.5 nsec) and that is overall 15% faster and requires 15% less hardware; their design is designated AEC/360 (or AEC-360) for Amdahl-Earle Computer ... snip ... from this (mostly discussion of failed future system): http://www.jfsowa.com/computer/memo125.htm The 370 emulator minus the FS microcode was eventually sold in 1980 as as the IBM 3081. The ratio of the amount of circuitry in the 3081 to its performance was significantly worse than other IBM systems of the time; its price/performance ratio wasn't quite so bad because IBM had to cut the price to be competitive. The major competition at the time was from Amdahl Systems -- a company founded by Gene Amdahl, who left IBM shortly before the FS project began, when his plans for the Advanced Computer System (ACS) were killed. The Amdahl machine was indeed superior to the 3081 in price/performance and spectaculary superior in terms of performance compared to the amount of circuitry.] ... snip ... above references general ACS with overview: http://people.cs.clemson.edu/~mark/acs.html also in acs-end article (from Amdahl interview): The single highest speed computer was a loss leader. The second smaller computer added made a break-even program. Adding the third even smaller computer came out with normal profit! IBM management decided not to do it, for it would advance the computing capability too fast for the company to control the growth of the computer marketplace, thus reducing their profit potential. I then recommended that the ACS lab be closed, and it was. ... snip ... past FS posts: http://www.garlic.com/~lynn/submain.html#futuresys -- virtualization experience starting Jan1968, online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
