Date: Tue, 13 Oct 1998 18:27:07 -0700 From: Mike Smith <mike@smith.net.au> To: Terry Lambert <tlambert@primenet.com> Cc: mike@smith.net.au (Mike Smith), karpen@ocean.campus.luth.se, hackers@FreeBSD.ORG Subject: Re: BETA problems... Message-ID: <199810140127.SAA02688@dingo.cdrom.com> In-Reply-To: Your message of "Wed, 14 Oct 1998 01:14:50 -0000." <199810140114.SAA21361@usr08.primenet.com>
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> > > _Is_ it fixed in new boot code, perhaps? > > > > No. It's almost impossible to get the distinction right. > > > > The difficulty lies in working out which physical drives the BIOS > > numbers correspond to. Unless you have a *very* new system, there is > > simply no way to know that the BIOS drive 0x81 is in fact wd2. In > > order for this to work, the user has to provide the missing data, > > either by typing 1:wd(2a)kernel every time (tedious) or putting it in > > /boot.config. > > Actually, you could MD5 the first N sectors of the disk using both VM86() > I/O and kernel I/O, and if the MD5 matched, you've found your drive. Given that we've established that disk I/O via our vm86 interface is problematic (you were part of this discussion, remember?), this is a non-possibility. It'll have to be done by the bootstrap. > If you have two drives that MD5 the same, tweak an unused portion > of one of them using VM86() I/O and see which one got tweaked using > kernel I/O, and, again, you've found your drive. Define "unused". > It's *not* impossible, since this is how Windows 95/98 converts > fd's opened using the INT 21 based I/O in AUTOEXEC.BAT to fd's > that, when INT 21 I/O is done to them in protected mode (via thunk) > into calls to the protected mode disk drivers and IFS layer (VFAT, > VFAT32, etc.) instead. Int 0x21 I/O doesn't use BIOS unit numbering, it uses DOS unit numbering. The folks in Redmond have access to a lot more information than I/we do, not to mention that if they break something, it's the broken party's problem. We don't have that luxury. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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