[email protected] (Shmuel Metz , Seymour J.) writes: > Virtual multiprocessors go back to the late 1950's[1] and early > 1960's[2], although IBM and Intel came late to the game. > > [1] Honeywell 800 > > [2] Peripheral Processors on CDC 6600
re: http://www.garlic.com/~lynn/2012d.html#73 Execution Velocity not 50s, but this old post on dual i-stream 195 keeping execution units fed: http://www.garlic.com/~lynn/2004e.html#1 A POX on you, Dennis Ritchie!!! in a.f.c. news group ... references the 1-bit flag in the pipeline as red/black instruction streams (as part of common pipeline keeping track of which instructions/registers were associated with which instruction stream) ... and believing it appeared in IBM's ACS project from early 60s ... but I can't find any mention at ACS reference site (IBM Advanced Computing Systems -- 1961 - 1969) http://www.cs.clemson.edu/~mark/acs.html however above does mention ACS and out-of-order instruction execution that appears in 360/91. Part of the current environment is deep-pipeline, dual instruction streams, out-of-order execution, speculative execution (re: conditional branches) and decomposing into RISC micro-ops ... provides execution units with a queue of large tens of pending operations for execution ... and if some operation stalls with a cache miss (and requires latency of storage fetch) ... there are a large number of other pending operations that may be executed (helping mask cache-miss, main storage fetch delay/latency). ACS timeline http://www.cs.clemson.edu/~mark/acs_timeline.html as in above timeline Amdahl resigns from IBM sept. 1970 ... supposedly as result of decision not to do ACS. Claims have been that Amdahl was not aware of the subsequent "Future System" effort that was going to completely replace all 370 ... but at a seminar he gave at MIT in the early 70s (several of us at the science center attended), he was asked what justifications did he use with investors for his new clone company. He mentioned that customers had already invested several billion dollars in 360 software development, and even if IBM were to completely walk away from 360(/370), that software base would keep him in business until the end of the century (which could be claimed to be a veiled reference to "Future System"). misc. past posts mentioning Future System http://www.garlic.com/~lynn/submain.html#futuresys for more topic drift ... additional Future System details: http://www.cs.clemson.edu/~mark/fs.html This claims motivation for Future System effort was clone controllers: http://www.ecole.org/Crisis_and_change_1995_1.htm from above: IBM tried to react by launching a major project called the 'Future System' (FS) in the early 1970's. The idea was to get so far ahead that the competition would never be able to keep up, and to have such a high level of integration that it would be impossible for competitors to follow a compatible niche strategy. However, the project failed because the objectives were too ambitious for the available technology. Many of the ideas that were developed were nevertheless adapted for later generations. Once IBM had acknowledged this failure, it launched its 'box strategy', which called for competitiveness with all the different types of compatible sub-systems. But this proved to be difficult because of IBM's cost structure and its R&D spending, and the strategy only resulted in a partial narrowing of the price gap between IBM and its rivals. ... snip ... Ferguson & Morris book, "Computer Wars: The Post-IBM World", Time Books, 1993, mention that distraction of Future System and killing off work on 370 products ... and then after Future System was killed with delay in getting 370 efforts restarted, allowed clone processors to gain market foothold. some discussion of restarting 370 efforts (3033 & 3081) http://www.jfsowa.com/computer/memo125.htm for other topic drift ... as undergraduate in the 60s, I had extended cp67 terminal support to include tty/ascii ... and tried to do something with the 2702 terminal controller that it couldn't quite do. This was somewhat behind university effort to do a clone controller (started with an Interdata/3 minicomputer) that would (at least) support both automatic terminal type identification as well as automatic line speed identification. this is picked up as product and sold as clone controller by Interdata (later bought by Perkin-Elmer and marketed under their brand name) ... four of us at the univ. get written up as responsible for (some part of) clone controller business. misc. past posts http://www.garlic.com/~lynn/subtopic.html#360pcm -- 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
