Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!husc6!yale!mfci!rodman From: rodman@mfci.UUCP (Paul Rodman) Newsgroups: comp.arch Subject: Re: In defense of the VAX Message-ID: <653@m3.mfci.UUCP> Date: 20 Feb 89 19:05:16 GMT References: <4592@tekgvs.LABS.TEK.COM> <638@m3.mfci.UUCP> <11037@tekecs.TEK.COM> Sender: rodman@mfci.UUCP Reply-To: rodman@mfci.UUCP (Paul Rodman) Organization: Multiflow Computer Inc., Branford Ct. 06405 Lines: 86 In article <11037@tekecs.TEK.COM> andrew@frip.gwd.tek.com (Andrew Klossner) writes: >Paul Rodman at Multiflow (rodman@mfci.UUCP) writes: > > "Personally, I think the vax has about the worst possible > archtecture one could come up with ... > >The disrespect expressed here is disturbing. Oh, foo. > The VAX design was an >excellent job for the project's objectives. That's nice. Maybe the project's objectives totally ignored the future? I'm not going to sit here and claim that at the time *I* knew what to do, but I'm just amused that such a large group of minds could completely ignore the fact that SRAM and DRAM improvements were going to make instruction set bit effectiveness much less important than the vax seems to think it is. It *is* a second order effect. I'm also surprised that they didn't realize that implementing a pipelined version of the vax architecture would be made more difficult with such a large set of byte aligned variable length instructions. I'll wager that a factory-cost / performance analysis of various machines would show that the high-end vaxes are worse than just about any other machines in that absolute performance range. Some of this might be due to the architecture, you know! >The measure of this is the >outstanding customer acceptance that the VAX architecture has achieved >over the last decade. Wrongo. All it shows is that the architecture is just one *small* facet in the success of a new computer from DEC. How much more money would would DEC have made had the 8600 cost 30% less in factory cost? Or had it come out 2 years earlier? The architecture would have affected both. How might the first micro-vax have performed had the architecture been different? > >To stand here, ten years later, and take pot shots at the VAX is rather >like criticizing Henry Ford for leaving radios out of the model T. > Look, you don't think there weren't any parts in the model T that could've been done better? I'm supposed to be so awed by the model T's success that I ignore the inevitable mistakes and bad compromises in the design? It couldn't have been improved? Of course it could, and I'm sure you agree here. My function EVER SINCE I've been an engineer is to take "pot shots" at the vax. Every machine I've worked on has competed directly against a high-end vax. You must be bugged because you feel I am stating: "the vax arch. design crew were stupid people". This is not true! All I'm trying to say is that often in engineering we struggle to use "scientific" ways of making our tradeoffs. Often, in hindsight, all the analysis is wonderfully detailed, and misses some much more important point(s) completely. And very, very intelligent people can totally miss the boat. One of the good things about the free enterprise system is that we can recognize the errors-of-our-ways and change them quicker than other systems can. That is why we *have* the Suns and Mips and Multiflows etc. I'm *not* personally trashing on anyone. But permit me the right to think that I can do it better. There is no *personal* "disrespect" intended. An interesting thought experiment would be to take the same group of people, get them in a room and say "If you were transported back in time and could know what you know now, what kind of machine would you build?". If they don't build something very vax-like, then was it worth all that thought/analysis? Or did they really need less people and better intuition(s) about hardware/compiler directions for the future? Paul Rodman rodman@mfci.uucp