I believe the main problem of today's BIOSes is that they're designed to
run in
real mode. A protected mode OS will either have to switch to and from real
and
protected mode to perform I/O (which isn't very neat, and incurs quite a
lot
of execution overhead) or ignore the BIOS entirely and provide its own I/O routines (which is a waste of coding effort). It'll be good if there's a
BIOS
that can provide some sort of protected mode framework (possibly amounting
to
a microkernel?) within which an OS can access BIOS services in true
protected
mode. (Proprietary ROM BIOS extension cards will probably have to be
modified
to fit into this scheme, but that's another story...)
That's been done in 1987, the so called ABIOS (advanced BIOS) in IBM's PS/2 systems. It was intended to be for OS/2. I don't know whether it got used at all, but the idea died together with the Microchannel architecture. Nobody missed it ever since...
Today's protected mode OSs use their own drivers to avoid switching modes. And switching modes on 386 and later CPUs is much faster than it was on the "brain-damaged" 286.
-------------------------------------------------------------------- Pascal Dornier pdornier@pcengines.com http://www.pcengines.com Your Spec + PC Engines = Custom Embedded PC Hardware --------------------------------------------------------------------
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