Curt @ Atari Museum wrote:
Quick question - can DOSbox handle older PC programs
that were meant to
run on old AT 8mhz speed machines? I've got a lot of the Atarisoft IBM
game titles on 5.25"s and they run insanely fast on a modern PC, I'd
like to be able to run them at a properly throttled speed.
Yes. In fact, myself and a few others have done significant work trying
to get CGA properly emulated (composite CGA emulation is pretty damn
close to the original; some tweaked modes work as well). It can even
boot bootable diskette images (as long as copy protection is absent).
The problem you may encounter with a fixed-speed game is that it is very
hard to dial the number of cycles per second to get a "nice" 4.77MHz
speed. DOSBOX is not cycle-exact, and some things (like memory
operations) are *much* faster than on the real hardware. The best you
can do is to run some sort of looping benchmark (a benchmark that
displays results repeated) and then use ctrl-f11 and ctrl-f12 to dial
the cycles up and down until you get what you want. I have found a
cycle setting of 233 most closely emulates a 4.77MHz machine, but it
depends on the game as to how faithful it is to the original.
To my knowledge, there are no 100% cycle-exact early PC emulators.
Tand-Em is very close, but a hassle to run; MESS is also close, so you
might want to check that as well.
One thing DOSBOX can do for you is "fix" the older games. Some older
games simply run too slowly on a 4.77MHz machine to be enjoyable, like
some 3-D titles like Vette! or Starglider 2. For those, you can just
speed the machine up a little bit and try running the game again until
get you get a comfortable framerate.
--
Jim Leonard (trixter at
oldskool.org)
http://www.oldskool.org/
Help our electronic games project:
http://www.mobygames.com/
Or check out some trippy MindCandy at
http://www.mindcandydvd.com/
A child borne of the home computer wars:
http://trixter.wordpress.com/