rehrauer@apollo.HP.COM (Steve Rehrauer) (08/02/90)
In article <713@cvbnetPrime.COM> jshekhel@feds19.UUCP (Jerry Shekhel ) writes: >I wasn't talking about supervisor mode. I was talking about hardware >support for multitasking with an isolated memory space for each process. >And besides, certainly, we can always throw more hardware at the problem. >We could use a real MMU on the ST, just like we could put a 386 processor >board into an 8086 machine. But I still haven't come closer to under- >standing why people on this newsgroup hate the Intel processor, when the >Intel/Motorola lines are so similar in terms of performance. (I tried email several times; it bounced. Oh well, everyone else has probably already k'd this subject by now...) Jerry, people who Just Run Code have no reason to prefer either line, assuming equal software. People who write code, in particular code-generators or assembly-language, have plenty of reasons to the despise Intel architecture. In short, segmented memory models suck. So do non-orthogonal instruction sets, where 'this' instruction does 'that', but only with 'thus' register or 'yonder' addressing mode. The Moto architecture is far from perfect in this regard, but it's a helluva lot cleaner. After doing code-generators for both segmented (Prime) and flat (Motorola 68k) models, as well as assembly-language for segmented (Prime, Intel) and flat (Moto), I think I can say that I speak from experience. Assuming that the average net.reader is far more inclined to poke "under the hood" of a pee-cee than the average Just.Code.Runner, I think it's very understandable that so many of the former are Moto fans. If, as you say, the criteria is to Just Run Code -- or even to just write fairly benign, high-level language code -- then I agree with everything you say. But if one is inclined or forced to dance more directly with the architecture, and I'm saying nothing about DOS vs Unix, then there's bushels of reasons not to like Intel's 80x86 line. Everyone should know what camp they're in, so why waste time trying to prove you're in the right one? We now return you to your regularly- scheduled ST/STe/TT/ATW/Portfolio/Lynx speculations... (Speaking of the Lynx, anyone notice that NEC -- I think it was NEC -- is advertising a handheld version of their game unit, complete w/ color screen? The Lynx didn't have the color handheld market to itself long. Pity Atari doesn't seem to be beating the Lynx drum loudly enough, early enough -- it's a slick-looking little box...) -- >>"Aaiiyeeee! Death from above!"<< | (Steve) rehrauer@apollo.hp.com "Spontaneous human combustion - what luck!"| Apollo Computer (Hewlett-Packard)
gl8f@astsun9.astro.Virginia.EDU (Greg Lindahl) (08/03/90)
In article <4bf5fd1a.20b6d@apollo.HP.COM> rehrauer@apollo.HP.COM (Steve Rehrauer) writes: >Jerry, people who Just Run Code have no reason to prefer either line, assuming >equal software. Actually, we do, because the software sometimes isn't equal. MS-DOS machines have big problems with programs that want to use more than 640k. You can write such programs for people who own the right hardware, but it takes an extra effort. So programs like TeX which like lots of memory take extra effort to port. What's the result? TeX has been out for free on the ST for quite a while. If you have a big document, buy more RAM. TeX for the PC is available for free, but it has a severe memory limit. I don't know if a PD TeX exists now that breaks the memory limit, but several years back it didn't exist. So you have to split your document up into little chunks. The memory limit affects other programs, too. Maple is available for the ST... and 386 PC's. Not 286 machines, even though a 286 machine could have much more memory and CPU speed than an ST. I would presume that the reason that Maple was never ported to the 286 was that it would require a lot of changes to deal with the memory model. It was cheaper to just compile it on the ST and 386's than change the code. Yes, you can buy many other symbolic algebra packages for MS-DOS. But if you have written a bunch of stuff under Maple on your Sun and you want to take it home for as cheap as possible, the ST or Amiga can do it while a 286 can't. Please don't bother to flame me about the prices of 386 machines these days. I can read Computer Shopper just like you can. -- "In fact you should not be involved in IRC." -- Phil Howard