Date: Sat, 23 May 1998 21:25:12 -0700 From: Mike Smith <mike@smith.net.au> To: freebsd-small@FreeBSD.ORG Subject: Re: BIOS bootstrap? Message-ID: <199805240425.VAA04131@antipodes.cdrom.com> In-Reply-To: Your message of "Sat, 23 May 1998 12:00:52 EDT." <Pine.BSF.3.95.980523115933.11594A-100000@neuron.hippocampus.net>
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> > > This is a tiny bit off-topic for the list, but I thought I'd throw it out > > > there... > > > > > > My embedded system supports BIOS extension and includes it's own local > > > Flash memory to do so. Basically what I'd like to do is build some sort of > > > (EE)ROM bootstrap to load my custom FreeBSD operating system. HOWEVER... > > > > > > All input/output must be done via COM1. I've never done much low level PC > > > programming...has anyone attempted something like this? In an ideal world, > > > I'd also be looking to front-end the BIOS setup screen over COM1. > > > > > > And, no, I can't just get a BIOS kit and re-write the BIOS :-p > > > > The FreeBSD bootstrap already supports serial console I/O, and FreeBSD > > has always supported serial consoles. You can tweak the bootblock > > build to always use com1 for I/O, and then set the appropriate flags in > > the kernel to use com1 as the serial console. > > Sorry, I guess I wasn't very clear... > > I'm talking about system bootstrap stuff *before* the FreeBSD > bootstrap...i.e. showing some sort of POST output, allowing the user to > possibly tweak some BIOS settings, etc. all over a console. You would have to hijack the video BIOS (steal its vectors, presuming the system BIOS calls it 'legally') and shadow the screen using a nominated terminal emulation. Given you can write BIOS extensions, that's not impossible, but it is quite a lot of work, and if you're not familiar with low-level PC bitbashing you have quite a lot to learn. (That's not intended to discourage you - just some perspective.) -- \\ 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-small" in the body of the message
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