Re: [OpenBIOS] serial console

[Benjamin Scott]

Dean Gaudet wrote:
> The best idea I've ever heard for a serial console on a PC is an ISA video
> card that behaves like text-mode VGA only,

While it would be a good idea, it has two problems: Cost and kludge. 
Such a thing is going to cost a good amount of bucks, being so rare, and
it really is a kludge to support weirdness on IBM-PCs.
> Even full screen stuff is possible:

Reminds me of the old DOS DOORWAY program for BBSes.  :)
> Remember that ISA/PCI cards have bioses on them, and those bioses expect
> to play with a video card.

I have seen a system boot headless (no video at all), but yes, most
software and some hardware expects to be able to play with video
memory.  One solution is to just not use (or fix) such
hardware/software.  Another is a software version of your above serial
console card.  Hardware and software doesn't really want to talk to a
video card, just be able to write directly to video memory (and maybe
play with a couple of video registers).  I am fairly sure we can create
a region of "video memory" from the BIOS for such stuff.  We could then
either attempt to convert it to serial, or just ignore it, depending on
specific needs.  The video registers I'm not sure about; can we hack
together an emulator for them using just BIOS code, or do we need actual
hardware?
> Plus you've got a more reliable method of generating an NMI/reboot which
> you'll absolutely need.

Why?

-- Ben

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