31 Jan
2006
31 Jan
'06
3:30 p.m.
mbbrutman-cctalk at brutman.com wrote:
While discussing this beast, the topic of putting a
CD-ROM on it came up. (I
would never do such a thing except for giggles.)
I've successfully used my Sound Blaster Pro + 1X CDROM drive to play
Sherlock Holmes (a video title, no less) on a 12MHz 286, so it is
possible. 1X is, as I'm sure you remember, 150KB/s.
As for giggles, it's really useful. Most 286s don't have 650MB of
storage :-)
Well, let's go throught some quick math. 6
million clock cycles per second is a
lot, but when you consider that each transation on the bus takes 4 to 5 cycles,
and instructions take 4 to 5 cycles (average) on a 80285, the throughput might
not be so hot.
Don't forget memory timing. Different boards/manufacturers did
different things.
When writing to a hard disk, would this machine have
used a tight processor
loop, or would it have used DMA? Under what circumstances would it use DMA to
transfer data to a hard disk?
I believe the AT and later used tight processor loops as they beat the
speed of DMA but I could wrong.
--
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/