Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!elroy.jpl.nasa.gov!jarthur!uunet!mcsun!ukc!edcastle!dcl-cs!aber-cs!athene!pcg From: pcg@cs.aber.ac.uk (Piercarlo Grandi) Newsgroups: comp.arch Subject: Re: AT peripherals (was Tektronix shutdown & move away from 88k's??) Message-ID: Date: 2 Nov 90 16:02:37 GMT References: <2176@lupine.NCD.COM> <42310@mips.mips.COM> <1990Oct30.164155.10708@mozart.amd.com> <1990Oct31.182519.2795@zoo.toronto.edu> <16978@yunexus.YorkU.CA> Sender: pcg@aber-cs.UUCP Organization: Coleg Prifysgol Cymru Lines: 58 Nntp-Posting-Host: odin In-reply-to: davecb@yunexus.YorkU.CA's message of 1 Nov 90 14:32:26 GMT On 1 Nov 90 14:32:26 GMT, davecb@yunexus.YorkU.CA (David Collier-Brown) said: davecb> henry@zoo.toronto.edu (Henry Spencer) writes: [ .. about the problems with plentiful and cheap AT peripherals ... ] henry> You don't get hardware docs for them. In fact, more often than henry> not there *are* no hardware docs to be had, no matter how cozy henry> you are with the manufacturer: there are a couple of gnomes henry> chained in a back room who hack the 8088 assembler code in the henry> on-board ROM until it works -- hack as in "hacked to pieces with henry> an axe" -- and that ROM code is the only documentation on how the henry> board really works. Rotsa ruck trying to write a driver from henry> that. Well, this is a problem with anybody's boards, not just the funny ones in the PC/AT market. IBM does pretty good documentation on their boards and peripherals, but because they have had legal problems about it. Other big-name companies are not as good, and even if they do write documentation, it is often exceedingly hard to get at, and even if you get it, what you really have to work around are the microcode or design bugs -- just consider the problems with the VGA ones, or those in the 750 microcode. I don't find AT boards all that more difficult to work with than say DEC ones. Also, they are often based on "well" documented chips, and they usually provide direct access to those chips. The peripherals in the PC/AT market are not just boards -- also cases, power supplies, monitors, hard discs, floppies, etc..., that just by virtue of being sold to a large and competitive market are easier to find and cheaper to buy than the same things as relabelled for say the MacIntosh market. A lot of people stuff into Suns and other minis hard drives that they buy in the PC/AT market, for near-wholesale prices. davecb> Realize, please, that many AT peripherals have little davecb> intervention by the main cpu, and those which do tend to have davecb> rather small roms which are about half-full of code... This is also true -- black boxes. henry> (I haven't tried this myself, but people who have tell me that it henry> really is that bad.) It's pretty bad, but more power to disassemblers and bus watchers! :-/. davecb> I've worked on AT and PC ROMSs in a past life, and the code davecb> quality is at least horrible and may extend as far as davecb> ``frightening''. This is not especially true of PC/AT microcode and systems software. Unfortunately. A lot of big-name manufactuers are reluctant to release engineering documentation, such as source code, also because it is often so poor in quality. Well, talent, taste and discipline are the scarcest commodities in any branch of engineering or architecture... -- Piercarlo "Peter" Grandi | ARPA: pcg%uk.ac.aber.cs@nsfnet-relay.ac.uk Dept of CS, UCW Aberystwyth | UUCP: ...!mcsun!ukc!aber-cs!pcg Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk