Date: Fri, 1 May 1998 10:30:36 -0700 (PDT) From: Dmitry Kohmanyuk <dk@dog.farm.org> To: peter.jeremy@alcatel.com.au (Peter Jeremy) Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: VM architecture (was Re: Protected mode instructions which reduce Message-ID: <199805011730.KAA28217@dog.farm.org>
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In article <199804262144.HAA29582@gsms01.alcatel.com.au> you wrote: [...] > On Fri, 24 Apr 1998 06:22:59 +0000 (GMT), Terry Lambert <tlambert@primenet.com> wrote: > >The IBM VM architecture is logically complete -- that is, nearly all > >of the instruction emulation implementation is in hardware, > The VM kernel needs to provide a `virtual supervisor' mode. This can > be quite expensive in software, so IBM provided microcode assist units > which effectively made `virtual supervisor' mode part of the hardware > machine mode. Pity that modern microprocessors don't have writable > microcode. they do; modern Pentium series (starting with PPro if my memory serves me right) contain user-modifyable area. The Pentium F00F bug release from Intel specifically said that this bug has to be dealt with in software because Pentiums are not updateable. how much you'd have to pay for the docs is a different question ;_) -- "If, after extensive tweaking, your program is still too slow, try dropping a few 'sleep(-1)'s into it." --Craig Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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