thad@cup.portal.com (Thad P Floryan) (01/06/91)
res@cbnews.att.com (Robert E. Stampfli) in <1991Jan5.052841.3618@cbnews.att.com > writes: Actually, I would put the 3B1 and the 8Mhz 8086 (which would have a 16-bit bus) about on par -- the 3B1 turns just over 1000 dhrystones, while an AT&T 6300 turns about 875 (MSC 4.0). In today's world, neither of these numbers is impressive. B-b-b-but, we ALL know there are: 1. lies, 2. damned lies, and 3. benchmarks! True about the dhrystone numbers not being impressive. I have one 68020/68881 Amiga system here that's fairly impressive (cannot find the dhry results; must be mis-filed), and I've played with a bunch of 68030 and have seen several 68040 systems. But, in ALL my own tests of doing real work (compiles, I/O, multi-tasking,etc) the 3B1 outperforms a Mac II (68020/68881/68xxx (MMU)) running A/UX 1.* or 2.*, and is no slouch compared even to my office VAX 11/780 systems However, I remember running Unix for a whole department of perhaps 20 people on an 11/45, and the 3B1 would have run rings around that. So, it all is relative: if you need a real smoker, go buy a 386 box and pay for the extra horsepower. If you just want a solid Unix-in-a-box machine at the right price, I can't think of a better choice than the 3B1. In the general sense I would agree with you. As an overall system the 3B1 is quite decent even by contemporary standards. And it literally outperformed the WGS6386/25MHz running SVR3.2 in our Users' Group booth during last year's West Coast Computer Faire ... I had actually believed the 6386 had crashed, but it was still crawling along. You wouldn't BELIEVE the number of things that were running on the 3B1 there ... some clowns had started up a LOT of games, video demos, and other stuff while I left for awhile to view the show, and when I returned was wondering why it "felt" slow running GNU EMACS and gcc ... 'til I saw all the processes and windows that were obscured. Sheesh! Good ol' "kill -9 nn" cleared up that problem real fast! And the Goodguys gave a "LAN Manager" demo at AT&T, San Francisco, during the same meeting I spoke back in Sept. 1990. They also had a 6386 running UNIX acting as a server on StarLAN for a single 6300; man that system was s-l-o-w. I brought up my 3B1 running "essentially" the same software and, again, the 3B1 beat the pants off the 6386. I didn't have to say even a single word; it was obvious from people's expressions as I was mousing and keyboarding along. Even the "UA" on the 3B1 was MUCH faster than "FACE" on the 6386. ALL other experiences I had with other vendors' '386 machines brings me to the same conclusion: the 386 s*cks. And I'm not overly keen on the '486 either; gimme a 68030 or 68040 ANY day. I can afford *ANY* computer that I choose to buy, and I see NOTHING based on the Intel CPU chips that even remotely interests me. Now, I really, honestly, and truly do NOT want to start any "computer wars" pissing contests in this newsgroup; just had to endure a bunch of that crap when some NeXT bozos cluttered up the comp.sys.amiga newsgroups recently. All I'm going to say is that Intel CPU architecture does NOT lend itself to good and efficient systems as typified by the 8086, 80286, 80386, 80486; they apparently DO have a winner with the i860, but that's something new and completely different and not likely to be in "home" or "small-office" systems for awhile. And I'm NOT going to bring up the "math" problems in early (still shipping?) '486 chips. No, to forestall all the massive flames which I'm SURE will result from this posting, I'm going to list some of the facts for your studied consideration. Many of the following technical points were posted to another newsgroup by Dave Haynie, whose technical expertise I respect (he designs computers for a living). 1. Let's first address the "8086" and "80286" in every '386 and '486 chip. Intel had to make the '386 and '486 as compatible as they could, they had no other choice. Because of what are design flaws, the 8088/8086 architecture wasn't extendable. There is no user mode, and there is no real OS to hide any differences. That's a bad thing, and the Intel lines will be stuck with it for a long time; even the '486 had to make compromises to let MS-DOS stuff work, and all those folks running UNIX on the '486 will pay the price. Contrast that with the superiority of the Motorola architecture which lets the user take along the software investment AND take advantage of performance increases other than simply a faster clock. 2. As someone else has said before, it is impossible to both understand and appreciate the Intel architecture; Motorola utilizes memory-mapping while Intel uses Isolated I/O Dedicated I/O instructions are an extremely archaic concept. The only reason they existed on the 8088 in the first place was because the 8088 was designed to be relatively close to assembly-source level compatible with 8080/8085 machines. The use of this technique in the 8080 was mainly to get around address space limits (you could have 64K AND I/O devices at once), but it's a horrible waste of instruction decoding, and the rest of the world does fine without it. You will find that this architectural foolishness is just about nonexistant outside of the 80x86 family. Even other Intel chips, like the i860, do things the modern way, by memory mapping. I don't know of any modern microprocessor that supports I/O-only instructions. The generic objections to the Intel architecture, however, have absolutely nothing to do with I/O mapping. They have to do with segmentation. Segmentation is one of the more truely evil concepts in the microprocessor industry. Again, this was something Intel adpoted to make the transition from 8080 to 8088 less painful. It worked to that end, but has been causing endless pain every since. Motorola, which was in a similar position in the 70's, chose instead to scrap any notions of pseudo-compatibility with their 8-bit line, and instead do a 16 bit microprocessor correctly. Their solution was to make the programmer's model a full 32 bit model, rather than kludging around with a 16 bit model and some banking scheme (eg, everyone then knew that 64K of addressing wasn't enough). The end result has been that every subsequent generation of Motorola 680x0 uses the same programmer's model. Every generation of Intel 80x86, except for the 80386->80486 jump, has had a new programmer's model and special hardware modes to support the old models. The reason the 80486 has the same model as the 80386? The 80386 was the first 80x86 CPU to support a true 32 bit programmer's model, which made segments unnecessary. So there was no reason to change anything. The Intel 80x86 architecture isn't appreciated anywhere near the high end of any market. It's used by folks who find 80486 machines a good bang/buck, or by folks who find that the installed base of 30-40 million MS-DOS machines and growth of another 10 million or so a year tends to make rather esoteric programs available on the market. Or by people who don't know any better. But there are few, if any, people who choose 80x86 machines because they admire their architecture. And I'm willing to bet just as many people buy Ford Escorts for their styling. Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]
ahh@glyph.UUCP (Andy Heffernan) (01/09/91)
In article <37648@cup.portal.com> thad@cup.portal.com (Thad P Floryan) flames: [ quoting from Dave Haynie: ] > The generic objections to the Intel architecture, however, have > absolutely nothing to do with I/O mapping. They have to do with > segmentation. Segmentation is one of the more truely evil concepts in > the microprocessor industry. Again, this was something Intel adpoted > to make the transition from 8080 to 8088 less painful. It worked to The story I got, I think from Prof. Gimpel (ya'know, the Gimpel-Lint guy) back when he was a professor for a living (like two years), was that a key reason for the introduction of segmenting was the goal to fit the whole mess into a 40-pin package. Apocryphal? Maybe. -- ------------------------------------------------------------------------- Andy Heffernan uunet!glyph!ahh "In a daze, Buck clutched at his head. `Oh, how manly I feel,' he moaned."