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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!nntp.coast.net!fu-berlin.de!irz401!orion.sax.de!uriah.heep!news From: j@uriah.heep.sax.de (J Wunsch) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: what is MCD0? Date: 15 Jul 1996 22:34:13 GMT Organization: Private BSD site, Dresden Lines: 36 Message-ID: <4seh15$hn4@uriah.heep.sax.de> References: <4s6pkq$g05@zeus.crosslink.net> <4s8276$n33@uriah.heep.sax.de> <4sdmq1$9rj@piglet.cc.utexas.edu> Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) NNTP-Posting-Host: localhost.heep.sax.de Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: knews 0.9.6 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E nichols@ccwf.cc.utexas.edu (Stewart Nichols) wrote: > I've had interference from the mcd driver, also. I think the original > poster was actually asking, in effect, "Why does this mcd0 device, which > doesn't seem to exist in my machine, mess up my network card driver?". > > If someone who knows something about how the probes are done would > be willing to explain it, I would be interested in knowing how the > probes are performed. Because it's ISA. ISA is not a bus system, it's a plain disease. It resembles the bus systems of the micros of the early 80's running CP/M. It's an almost ``CPU local bus'', with only some wait states added for several bus access operations. No per-slot configuration registers or memory areas. Autoprobing was apparently not an issue for a CP/M system, you had to use a customized BIOS anyway. The formula is simple: any attempt to auto-probe some device on the ISA bus that requires even a single write operation to the bus is destructive. Even if you finally found out that the probed address doesn't belong to `your' device, you cannot undo you ramifications, leaving the actual device you were just stomping upon in a weird state. That's why the recommendation: make sure where your hardware is, and use the -c option to disable all unused drivers, and adjust the used drivers to match the reality. Everything else is a hazardous game. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)