Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!sharkey!edsews!uunet!sco!seanf From: seanf@sco.COM (Sean Fagan) Newsgroups: comp.arch Subject: Re: In defense of the VAX Message-ID: <2324@scolex.sco.COM> Date: 21 Feb 89 23:06:29 GMT References: <4592@tekgvs.LABS.TEK.COM> <638@m3.mfci.UUCP> <11037@tekecs.TEK.COM> <653@m3.mfci.UUCP> <1226@husc6.harvard.edu> Reply-To: seanf@scolex.UUCP (Sean Fagan) Organization: The Santa Cruz Operation, Inc. Lines: 39 In article <1226@husc6.harvard.edu> reiter@harvard.UUCP (Ehud Reiter) writes: >The most important thing about an architecture is that it >should make it easy for people to write and run programs, and I don't think >anyone has complaints about the VAX on this score. This contrasts with the >IBM 370-class machines, which suffer greatly from lack of address space, >which *is* very much an annoyance to the programmer and even the end-user. Your first statement there is the argument CISC advocates use. RISC advocates say that performance matters more, since most people will end up using a compiler more than assembly code (true, nowadays, but only because compiler technology has gotten *real* good). For the most part, the end-user doesn't care *what* the machines architecture looks like, as they just want performance. So, in that sense, the RISC people are correct. However, not providing a multiply instruction is *real* stupid (IMHO), because "real world" applications tend to do multiplies. Providing a POLY instruction is also *real* stupid (again, IMHO), since most "real world" applications don't do that (unless you're on a Cray, which, of course, doesn't provide a POLY instruction 8-)). Not providing an instruction can cause the compiler writers to throw their hands up in the air (watch me, sometime, when I take a look at the 370 instruction set), while providing excess instructions can (and usually do) slow the machine down. What's needed, of course, is a combination of the two (something like what the CDC Cyber's had, or possibly what an Elxsi has): RISCC, Reduced Instruction Set Complexity Computer (I know, I know, I'm not the first one to say this). This way, compiler people will get the instruction set they need (case study: the Elxsi), and applications people will get the speed they want. The world needs a 64-bit Cyber-like Personal Computer (with, of course, a $1k price tag) 8-). -- Sean Eric Fagan | "What the caterpillar calls the end of the world, seanf@sco.UUCP | the master calls a butterfly." -- Richard Bach (408) 458-1422 | Any opinions expressed are my own, not my employers'.