Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!spool.mu.edu!uunet!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.advocacy Subject: Re: 8-bit death Message-ID: <21135@cbmvax.commodore.com> Date: 1 May 91 20:46:20 GMT References: <1991Apr28.122439.13393@sugar.hackercorp.com> <1991Apr28.162045.15585@daffy.cs.wisc.edu> <1991Apr30.112820.2451@sugar.hackercorp.com> <1991May1.064455.3058@kessner.denver.co.us> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 66 In article <1991May1.064455.3058@kessner.denver.co.us> david@kessner.denver.co.us (David Kessner) writes: >In article <1991Apr30.112820.2451@sugar.hackercorp.com> peter@sugar.hackercorp.com (Peter da Silva) writes: >>In article <1991Apr28.162045.15585@daffy.cs.wisc.edu> dinda@cat55.cs.wisc.edu (Peter Dinda) writes: >>I love it how these college freshmen are so bloody sure of themselves. >What makes _YOU_ so sure? Scars acquired over years of working "in the business" are a reasonable assurance. >>As far as the programming model (the only one that counts) is concerned, >>the 8088 is an 8-bit processor with 4 bank-select registers built in. >In _every_ respect, the 8088/8086 is a _16_ bit CPU. No, the 8088 is, of course, an 8 bit CPU from the hardware viewpoint. Every chip can be viewed from the hardware prespective (what pins are on the actual chip), the chip architecture point of view (ALU size, etc.) or the software point of view (eg, programmer's model). >I'm sure that in the late 1970's this seemed to be the reasonable thing to >do, however hindsight shows it in a different light. It was obviously not reasonable to anyone but Intel. They felt it was reasonable because it made the 8086/8 assembly code very similar to 8080/5 assembly code. >I really must say, however, that the addressing of the CPU has no effect >on the number of bits that the OS "is". Only because it's impossible to represent the "size" of any OS as a single number. At the very least, you need separate numbers for the addressing and operation size of an OS. That makes MS-DOS a 20/16 bit OS, the Amiga OS a 32/32 bit OS, Mac OS (at least System 6 and below) a 24/32 bit OS, etc. according to this particular model. But even that's an artificial measure for the most part. >It is also a common mis-conception that the PC's intterupts are somewhat >lacking. Well, the only thing they lack is a limit of 15 intterupt sources >on the ISA bus. No, actually, it is well documented FACT that the PC's interrupts are brain damaged. The whole point is that they are positive edge sensitive interrupts, and therefore can't be shared. The whole industry has pretty much decided that level sensitive, active low, shareable interrupts are a much better idea, long before the PC showed up. >>No. Actually, MS-DOS is worse than CP/M. CP/M never got caught into the trap >>of becoming specific to one piece of hardware. >Wasn't CP/M specific to Z80 (and the like) CPU's? I don't know which is >worse, Z80 or MS-DOS... CP/M was specific to any Z-80 computer it had been ported to. MS-DOS is specific to any 8088 computer, as long as that computer is an exact clone of the IBM PC. See the difference? CP/M was processor dependent, but not system dependent. MS-DOS, for all intents and purposes, is system dependent, as the owners of Tandy 1200s or Mindsets could well attest to. >>Peter da Silva. `-_-' >David Kessner - david@kessner.denver.co.us | do { -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "That's me in the corner, that's me in the spotlight" -R.E.M.