Date: Thu, 25 May 2000 08:27:47 -0700 From: Peter Wemm <peter@netplex.com.au> To: Warner Losh <imp@village.org> Cc: Chuck Paterson <cp@bsdi.com>, arch@FreeBSD.ORG Subject: Re: Preemptive kernel on older X86 hardware Message-ID: <20000525152747.AFBF21CE1@overcee.netplex.com.au> In-Reply-To: Message from Warner Losh <imp@village.org> of "Thu, 25 May 2000 09:01:26 MDT." <200005251501.JAA01183@billy-club.village.org>
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Warner Losh wrote: > In message <200005241446.IAA05589@berserker.bsdi.com> Chuck Paterson writes: > : Once FreeBSD has a preemptive kernel FreeBSD will only run on > : Pentium or better X86 processors. > > This is likely unacceptible in the embedded market. We're using > boards with a UP 486 133's on them (actually AMDs, but you get the > idea). We need some way to build kernels for these boxes. It sure > would be nice, but isn't required, to have the same kernel for pentium > UP machines. While I think we need to be able to support 386 and 486 still, I'm moderately sure that we could get away with de-supporting those in GENERIC for 5.0+, assuming that it buys us something. I would not have too much trouble with a proposal that a I386_CPU and maybe I486_CPU becoming mutually exclusive with the 586+ stuff. ie: if you will still be able to build a kernel specifically to run on a 486, but by default it would not fly. I think 586+ is a convenient boundary because I am not aware of many 586's that don't have PNPBIOS support, while 486's are mixed as they predate win95 by a fair way. Aiming for a default fresh-install target (remember, 5.0 is 6-12 months away) where we require minimum 586+ and PNPBIOS etc etc would simplify things a fair bit.. In such a scenario it should still be possible to build a kernel to specifically support an i486 on a non-PNP isa-only system without PCI etc. I have a 486 still running and would hate to loose it for sentimental reasons, but I do custom builds for it anyway. I strongly doubt that there will be many *fresh* 486 installs, if any at all. But that is changing the subject. :-) > I would have no problem saying SMP is only supported on Pentiums or > newer. I don't think we support 486 SMP right now, but I could be wrong. > Warner Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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