Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!amdcad!sun!pitstop!sundc!seismo!uunet!mcvax!ukc!reading!onion!cf-cm!mch From: mch@computing-maths.cardiff.ac.uk (Major Kano) Newsgroups: comp.arch Subject: Re: Is the Intel memory model safe from NO-ONE ?!? Summary: Clearing the air a bit. Keywords: 386 intel memory protection management model segmented Message-ID: <401@cf-cm.UUCP> Date: 18 May 88 12:37:39 GMT References: <1806@obiwan.mips.COM> <2904@omepd> <353@cf-cm.UUCP> <3450@omepd> Reply-To: mch@computing-maths.cardiff.ac.uk (Major Kano) Followup-To: comp.arch Organization: University College Cardiff, Wales, United Kingdom Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!amdcad!sun!pitstop!sundc!seismo!uunet!mcvax!ukc!reading!onion!cf-cm!mch From: mch@computing-maths.cardiff.ac.uk (Major Kano) Newsgroups: comp.arch Subject: Re: Is the Intel memory model safe from NO-ONE ?!? Summary: Clearing the air a bit. Keywords: 386 intel memory protection management model segmented Message-ID: <401@cf-cm.UUCP> Date: 18 May 88 12:37:39 GMT References: <1806@obiwan.mips.COM> <2904@omepd> <353@cf-cm.UUCP> <3450@omepd> Reply-To: mch@computing-maths.cardiff.ac.uk (Major Kano) Followup-To: comp.arch Lines: 118 In article <3450@omepd> mcg@iwarpo3.UUCP (Steve McGeady) writes: > >In article <353@cf-cm.UUCP> mch@computing-maths.cardiff.ac.uk (Major Kano) writes: >> This is a partial reprint of an article that I posted in mid March. ... >> >>In article <2904@omepd> mcg@iwarpo3.UUCP (Steve McGeady) writes: >>> >>>It can't be elegance of design, for (e.g.) the 80386 and the MIPSco processor >>>are each somewhat inelegant in their own ways (for those who don't wish to >>>fill in the blanks, segmentation and register model in the former case, >> ^^^^^^^^^^^^ ^^^^^ >> ** WHAT THE $@#@++%%& HELL ?!? ** >> > >After having taken the above quote completely out of context, Mr. Howe then >goes on to attempt to rekindle the justifiably extinct *86 memory model >discussion. > >To set the record straight, yet again: > > 1) I was not implying that there is anything wrong with the 80386 > (or *86, for that matter) memory or register models, simply > that THERE MAY EXIST PEOPLE WHO BELIEVE that there is something > wrong. That particular rhetorical distinction is apparently > lost on Mr. Kano. I no longer have a copy of the original article. Maybe I'm slow, but I can remember nothing in it to suggest that the remark about elegance was anything but Mr. McGready's own opinion. I can see that it was not the point of his article, but this was the first criticism of the segmented model that I'd seen on the net, and so I replied to it. The reason I "took it out of context" was that I was only interested in the segmenting vs linear/paging aspect, rather than in Mr. McGready's article as a whole. I was not attempting to ascribe to Mr. McGready any opinions that he had not expressed, and I aplologise to you, Mr. McGready, if that was the impression that you (or the net) got. As for the "justifiably extinct" discussion, I consider that since I had never seen a * rational * comparison between segmenting and linear/paging, and that a recent "Byte" article on the 80386 and Unix made a "sort-of" comparison that the issue of segmenting * in general * and its various implementations is clearly NOT extinct. The repiles to and postings about my article that I have seen on comp.arch and received (via e-mail) so far tend to support that view. As for the *86 memory model * in particular *, I dont' think anyone would disagree that the implementation of segmenting on the '286 is poor, and that the 8086/8/186/188 "segments" are not segments at all. Since in the micro world, Intel are the main proponents of segmenting, it is inevitable that their processors will be the ones against which all others are compared, whether favourably or not. Also, one tends to mention the processors with which one is familiar, when talking about something and quoting examples, and for a lot of us, the 80x86 series is just that, so again, the subject still has SOME life left in it. > > The point, perhaps worth repeating, is that there are some people > who are as aesthetically offended by the exposure of the pipeline > in the MIPSco processors as others are offended by segmentation, > etc. > > 2) The 80386 butters my bread, and will continue to do so for some > time. Yes, I got that point in Mr. McGready's followup to his original article. > > 3) Even if Mr. Howe's inference were correct, which it is not, I do ^^^^ > not speak for Intel Corporation. My views are my own, etc, and ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > often they are not even that, but temporarily adopted for > didactic discourse. Yes, I got that point in Mr. McGready's followup to his original article. > >[Mr. Howe then descends into discourse on the merits of segmentation, which >I have no interest in addressing.] > >As a final plea, it would be awfully nice if we could have a discussion on >the network that did not devolve into a semiconductor race war: my chip is >{bigger,faster,longer,stronger,prettier} than yours. Yeesh. I'm not sure what is meant by this. Is it being suggested that the segmenting vs paging/linear argument * on usenet * has become a "Motorola vs Intel vs The Rest Of The World" one (as I have seen happen in magazines) ? It does not seem to have done so far, but in case it does, I should point out that this was not my intention. I too, hope that the discussion stays architectural, rather than becoming confined to company vs company flames. (Of course people will have to mention specific examples in order to continue the discussion). Two people so far have mentioned "capabilites". What are they, please, so's I can continue to follow the discussion. Also, references have been made to a large linear address space, having (max segment length)*(no of segments) bytes in it. This occured to me a couple of weeks ago as a possible idea, but surely paging such a thing into a *MUCH* smaller physical memory (say, 16 Mbytes) might be difficult. Anyone got any ideas on this ? >S. McGeady >Intel Corp. I have seen many postings, and had a few replies. Perhaps I should point out that I was not really interested in the intel 80x86 with x<3, since these are becoming dead ducks. The 80386 is a nice machine, and should replace all other 86-series machines, in my opinion (tho' I bet it won't :-). If I see enough distinct followups and e-mail replies, I will post a summary. Thanks for the discussion so far. Regards to you all, -mch -- Martin C. Howe, University College Cardiff | "You actually program in 'C' mch@vax1.computing-maths.cardiff.ac.uk. | WITHOUT regular eye-tests ?!" -------------------------------------------+-----+------------------------------ My cats know more about UCC's opinions than I do.| MOSH! In the name of ANTHRAX!