Date: Thu, 3 Dec 1998 23:27:00 +0200 (SAT) From: Robert Nordier <rnordier@nordier.com> To: joelh@gnu.org (Joel Ray Holveck) Cc: rnordier@nordier.com, mike@smith.net.au, jkh@zippy.cdrom.com, Marius.Bendiksen@scancall.no, hsw@email.generalresources.com, hsw@acm.org, abial@nask.pl, freebsd-current@FreeBSD.ORG Subject: Re: /boot/loader what to set rootdev to? Message-ID: <199812032127.XAA18890@ceia.nordier.com> In-Reply-To: <86btllqfio.fsf@detlev.UUCP> from Joel Ray Holveck at "Dec 3, 98 11:52:47 am"
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Joel Ray Holveck wrote: > >>> Yes, we have been over this before. Would you care to explain how you > >>> plan to reinstate the vectors that the DOS7 kernel replaces so that > >>> vm86 BIOS calls from the FreeBSD kernel will work? > >>> Please understand that there are some really fundamental issues which > >>> absolutely preclude starting FreeBSD once DOS has been started. > >> We may have a different definition of "DOS7 kernel". I typically use > >> that phrase to refer to IO.SYS alone. The vectors seem to be modified > >> by HIMEM.SYS instead. By default, IO.SYS will load HIMEM.SYS and > >> prevent the kernel from loading. However, the line "DOS=NOAUTO" in > >> the config.sys will cause IO.SYS to skip that step. I have had > >> success loading FreeBSD by using that line in the PIF's specified > >> CONFIG.SYS myself. > > As you go on to describe, it is *not* particularly difficult to > > boot FreeBSD straight out of Windows. > > I want to make one point clear: the process *does* have an intervening > reboot between when Windows is loaded and when FreeBSD is loaded. OK. Booting out of Windows into a carefully prepared and disinfected DOS session has a chance of coming tolerably close to resembling a cold boot: at least with kernel vm86 usage as it is at the moment. But if one is exiting Windows in order to load FreeBSD, why boot into DOS anyway? (It's kind of like going to wash your hands before dinner, but then stopping off for a pee on your way back to the table.) I'm certainly not intending to knock anyone's interest in doing this. But to me, (like the hand-washing rule) looking for ways around the cold boot rule verges on the perverse. We already have a similarly-inspired "If you overclock your box, don't call us" rule. To actively encourage users to run FreeBSD on top of DOS (and whatever muck may have been swimming about in the DOS process space at the time) would be at least equally foolhardy. Because, with vm86 calls down along the real address mode interrupt chain, that's what it has the potential to amount to. To me, commonsense just says no. And I'm not trying to convert anyone else to that opinion: it's why I don't want to even *think* about this stuff any more. :-) -- Robert Nordier To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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