Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!ogicse!cvedc!mcspdx!adpplz!martin From: martin@adpplz.UUCP (Martin Golding) Newsgroups: comp.arch Subject: Re: VISC - A way to speed up moto cisc mpu's? Message-ID: <774@adpplz.UUCP> Date: 30 May 91 21:17:57 GMT References: <13445@dog.ee.lbl.gov> <1991May23.210000.8152@kithrup.COM> <2842@lee.SEAS.UCLA.EDU> <21621@brahms.udel.edu> Organization: ADP Dealer Services R&D, Portland, OR Lines: 48 In mac@gold.kpc.com (Mike McNamara) writes: > I've worked on two different commercially unsucessful >heterogeneous processor machines. I don't think that I am the common >thread of failure ;-) [description of two machines canceled due to lack of interest] > One common problem with both machines is that the benchmark >results did not justify the cost of the machine. AHA I just realised that I have useful information to contribute here. Here at ADP we built a _successful_ dual processor system; it ran a (disk-based) RT11 like operating system and (virtual memory based) Reality, simultaneously. For about 4 years they were our most popular single model. Our machine sold because we had just oodles of software for _each_ processor, and the cost and risk of rewriting was worse than the engineering for the computer. (Two systems types and a hardware engineer for the computer, 200 programmers working 5 years for the software). If the stuff had _all_ been in _one_ (preferably popular) language, there wouldn't have been any point. Moral: It's only worth building the dual processor machine if you _already_ have software that _can't otherwise_ be ported. See the interesting dos and cp/m add-ins for all kinds of interesting computers. Note also that binary converters and interpreters are gaining strength. Drawback: interesting software is currently produced for DOS and unix. Dos machines are dos machines, eh? And unix computers sell based on how many interesting packages get ported. So the demand for a RISC computer with 68xxx binary coprocessor is probably not worth the engineering. Besides, we get better stuff for our 88k's than for our 68k's; I think that the software porting types have a personal fondness for the RISC systems that biases the results. All of this has strayed very wide from the RISC vs CISC long term performance, which is heavily language dependent; unless someone wants to make vectorising compilers that extract string functions from c. Martin Golding | sync, sync, sync, sank ... sunk: Dod #0236 | He who steals my code steals trash. A poor old decrepit Pick programmer. Sympathize at: {mcspdx,pdxgate}!adpplz!martin or martin@adpplz.uucp