Date: Tue, 25 Jul 1995 09:06:34 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: amengual@cesca.es Cc: msmith@atrad.adelaide.edu.au, joe@via.net, questions@freebsd.org Subject: Re: Headless/keyboardless booting... Message-ID: <199507242336.JAA01071@genesis.atrad.adelaide.edu.au> In-Reply-To: <Pine.3.07.9507241639.A17119-a100000@prades.cesca.es> from "Carles Amengual" at Jul 24, 95 04:45:58 pm
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Carles Amengual stands accused of saying: > On Mon, 24 Jul 1995, Michael Smith wrote: > > In principle yes; I've noticed that some systems have problems booting > > without a keyboard though. > > AT-like PCs use a keyboard interrupt (I think is A20, though not sure) to > address RAM above ~1 MB, so FreeBSD (nor any other OS) should not be able > to work without a keyboard. Maybe this is no longer true for some PCs, but > I have not seen it. However, many newer PCs handle much better all this. This is just so totally confused it's not funny 8( A20 is an address line, not an interrupt. No systems (that I'm aware of anyway) use the keyboard to access any memory anywhere. A20 _is_ (obviously, really) used to address memory above the 1M mark, and is manipulated in an odd fashion in some modes. None have anything to do with the keyboard. What you're probably confusing this with is the trick that old versions of OS/2 used to return from protected mode to real mode on the '286. This has _nothing_ to do with FreeBSD, memory above 1M, A20 or my (badly wilted) geraniums. > Carlos Amengual, amengual@prades.cesca.es -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] My car has "demand start" - Terry Lambert [[
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