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Received: by minnie.vk1xwt.ampr.org with NNTP id AA6713 ; Tue, 12 Jan 93 11:20:56 EST Path: sserve!manuel.anu.edu.au!munnari.oz.au!sgiblab!spool.mu.edu!agate!doc.ic.ac.uk!uknet!yorkohm!minster!forsyth From: forsyth@minster.york.ac.uk Newsgroups: comp.unix.bsd Subject: dos bootstrap Message-ID: <727017058.5418@minster.york.ac.uk> Date: 14 Jan 93 13:10:58 GMT Organization: Department of Computer Science, University of York, England Lines: 18 actually, plan9 uses a .com not a .exe to boot; this is much easier to generate by cross compilation on a decent system. i do the same thing for my own o/s's bootstrap on the 386/486. plan9's booting from DOS is not enough to save it having to know about the hardware, since it takes the machine into protected mode itself. unfortunately the A20 hack implementation differs on many 386 implementations, and that undoes plan9's attempt to use DOS's boot to set everything up. my system's bootstrap manages a bit better -- it works on all our machines but plan9's bootstrap doesn't -- simply by using the BIOS to enter protected mode (although it took hours to get right all the details of that poorly-documented INT call). actually, plan9 would probably do nearly as well if it defaulted to the most common A20 arrangement, as the 386bsd bootstraps i've seen seem to do.