On Thu, Apr 29, 2010 at 5:20 PM, Chuck Guzis <cclist at sydex.com> wrote:
On 29 Apr 2010 at 15:34, Ethan Dicks wrote:
I'm starting to see some interest in
pre-Pentium systems from younger
enthusiasts who want to fiddle with DOS on bare metal...
As far as I know, DOS will run on almost any x86 PC, pre-Pentium or
not.
Yes. I haven't tried DOS on a Pentium4, but the problems I would
expect to see there are related to poor or non-existent BIOS and
hardware support for multiple floppy drives or drives other than
"1.44MB" capacities.
Sound-based applications might have problems with IRQs and PCI-only
machines - that was a pain point at the ISA->PCI changeover.
?The main difference to me is that the older systems
are slower
and generally have more ISA slots.
Or more specifically, _have_ ISA slots. I have a motherboard (Asus
A7V) that's 10 years old and has only 5 PCI and an AGP.
Some software has CPU timing loops, and that may make
a difference,
however.
Quite, but most of that was purged from the market when machines
started getting faster than about 16MHz. For 286s and 386s, there was
the "Turbo" button. I don't recall many 486s having an active Turbo
switch, and I don't remember seeing any Pentium systems that could be
slowed down that easily (though you could disable cache and pump up
wait-states and such in the BIOS).
?Games written for a 5150 set running on 3GHz PC can
be a
bit more--ah, challenging.
Indeed.
The first job I had was at the place that wrote "Wordvision", a word
processor for the PC (my job was to write the C-64 demo for Comdex).
Wordvision was written for a 5150 with 256MB or more, one floppy drive
or more, and DOS 1.0 "or better". It used timing loops for key
repeat. Someone came along after the company folded and wrote a patch
to let Wordvision run sanely on a 386. I think they just adjusted the
timing parameter to match the measured speed of the target machine so
that key repeat "worked as expected".
-ethan