IBM Advanced Computer Systems project: Difference between revisions

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Harwood Kolsky gave a presentation on the various competing designs, while [[Gene Amdahl]] and [[Chen Tze-chiang]] talked about their work on the high-end 360 Model 92. Kolsky had worked at Los Alamos for seven years before joining the Stretch project, while Amdahl had left IBM after being passed over to lead Stretch development but returned to IBM Research in 1960 and joined the Project X effort.{{sfn|Smotherman|Sussenguth|Robelen|2016|p=61}} In late 1964, Amdahl took a teaching position at [[Stanford University]], wanting to return to the west coast. In January 1965 he was named an [[IBM Fellow]] for his work on the Model 92. As a Fellow, Amdahl was entitled to work at any IBM facility of his choosing and decided to join ACS at the invitation of Bob Evans.<ref name=interview>{{cite journal |journal= IEEE Design and Test of Computers |date=April 1997 |title=Interview with Gene Amdahl}}</ref>{{sfn|Smotherman|Sussenguth|Robelen|2016|p=63}}
 
Even at this early meeting, Amdahl made the argument that it would make much more sense to make the ACS compatible with the 360, as had been the case with Project X. While it might run marginally slower than the ACS, due largely to it using ahaving sixteen 32-bit word and having 16 registers instead of 32thirty-two 48-bit ones in the new concept, it would offer customers of the Model 92 an upgrade path to much higher performance and leverage all of the software andfor the 360, especially theirthe [[compiler]] technology developed for that machine.{{sfn|Smotherman|Sussenguth|Robelen|2016|p=61}}
 
===Design matures===
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A final review was performed in April, but this was brief and seemingly already decided. In May, IBM announced the ACS-1 would be cancelled and the AEC/360, to be known as the ACS-360 from that point, would move forward. Although Amdahl's competing design had much to do with this, it was not the only reason. Amdahl had also argued that the $15 million would better be spent on improving the operating systems on the 360, which would improve the entire lineup, not just the AEC. But perhaps the most serious blow to the ACS was the continued success of the 360. In January 1968, [[NASA]] had taken delivery of a 360 Model 95, which IBM described as "the fastest, most powerful computer now in user operation."{{sfn|Smotherman|Sussenguth|Robelen|2016|p=67}} Although the ACS would have outperformed the Model 95 by a wide margin, by this time Watson Jr. was considering withdrawing from the supercomputer market entirely.{{sfn|Conway|2011|p=29}}
 
Many of the retrospective articles on the ACS project note that the original machine would have been a world leader. Conway notes that "In hindsight, it is now recognized that had the ACS-1 been successfully built, it would have been the premier supercomputer of the era."{{sfn|Conway|2011|p=20}} The decision to cancel the original design rested mostly on the cycle counts which had not been tested as the simulator she had developed had not been portedmodified to use the new instruction set.{{sfn|Conway|2011|p=20}} Likewise, Amdahl's claim of an 8 nanosecond cycle was accepted by the Conti review although Mark Smotherman suggests it is not realistic.{{sfn|Smotherman|Sussenguth|Robelen|2016|p=67}}
 
===Cancellation===
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Shortly after the announcement of the project's cancellation, in August 1969, IBM announced the [[IBM System/360 Model 195]], a re-implementation of the Model 91 using [[integrated circuit]]s that made it twice as fast as the [[IBM System/360 Model 85|Model 85]], which at that time was the fastest machine in the lineup. To address the high-end market, a [[Vector processor|vector processing]] task force was started in Poughkeepsie.{{sfn|Smotherman|Sussenguth|Robelen|2016|p=68}}
 
When the ACS project was cancelled, many of the engineers were not interested in returning to the main IBM research campus in New York and wished to remain in California. Some ended up at IBM's [[hard drive]] research facility in [[San Jose, California]], while many others left to form a new company, Multi Access System Corp, or MASCOR. This failed to raise capital and folded after only a few months.{{sfn|Smotherman|Sussenguth|Robelen|2016|p=68}} Amdahl resigned in September 1970 and formed his own company to build 360-compatible machines, introducing the [[Amdahl 470/6]] in 1975. [[Amdahl Corporation]] would become a major vendor of IBM-compatible systems into the 1980s, with a 20% or better market share through the 1970s and 80s.<ref>{{cite news |newspaper=The New York Times |title=AMDAHL IS STILL GUESSING RIGHT |date=22 May 1981 |first=Thomas |last= Lueck |url=https://www.nytimes.com/1981/05/22/business/amdahl-is-still-guessing-right.html}}</ref>
 
==Influence==