7 Apr
2007
7 Apr
'07
10:07 p.m.
Dave Dunfield wrote:
With wait states and cache turned off (INTERNAL cache, not L2, see the
ICD.COM util I mentioned earlier) my 486 is slower than my 5150. So you
probably missed the internal cache step.
Yes, very astute. If it's taking minutes per track to match track
length, then you muck with the computer and/or move the board to a
different machine.
The Option
Board was, IIRC, completely software-driven and extremely
susceptible to machine speed (and sometimes even interrupt noise, which
is why they made TCS.EXE which doesn't use EMS and might disable some
hardware interrupts as well). The fastest machine I could get it to
work in reliably was an AMD 386-40, with the ISA bus speed at either
clock/5 (8MHz) or locked at a timer clock integral divider (ie.
7.16MHz). If memory serves, I had the best results at 7.16MHz.
Currently I keep mine in my 5160.
I have the bus set to 7.16 Mhz, all the wait states I can get turned on,
cache turned off etc - but I think the 486 is still too fast for it. I heard
through the grapevine that, sadly, the creator of the Option
Board (everything, hardware to software) passed away in the mid 1990s,
so there is no official resource to ask about the OB. But it was always
one of my favorite peripherals, and just watching it try to match track
length while copying gave me some insight into FDC operation (and
protection methods!)
In my case, the board would take FOREVER to match the track length - another
clue that it's having timing problems - Often several minites/track - I had
Yes I did thanks - I believe thats where I got the newer software version.
Is there any detailed information available on the DOB (I understand the
OB and the DOB are different)?
They are, but all the info I have I've contributed to the aforementioned
site, and it was only OB info.
--
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/