ImageDisk update

Jim Leonard trixter at oldskool.org
Sat Apr 7 00:33:51 CDT 2007


Dave Dunfield wrote:
> PS: I found this while fooling with and old 486 because I finally
> decided to see if I could get my Central Point DEluxe Options Board
> working - the TRANSCOPY that I had for it wouldn't run at all (froze
> during the analyze phase), but I downloaded one from the net which
> does, but I have been unsuccessful in actually recording and
> recreating a plain-jane DOS DD 360k disk - I've gotten it to complete
> the motions a couple of times but the result has errors in it.

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.

Trivia:  Central Point received legal pressure from companies late in 
the Option Board's life; as such, later revisions of the software, while 
more compatible with faster machines, actually copy *less* protection 
methods -- and in a few cases, will copy a diskette such that the copy 
will work but copies of the copy will not.  So my usual operation with 
the OB is to use the latest version to make a backup copy; if that 
fails, start going backward through revisions until I find one that works.

I have only come across one protection method the OB cannot duplicate 
(other than laser holes, of course):  Cop's Copylock II.  It was used 
mostly in Europe.

> This is a 486/25 (slowest I could make it) - does anyone know if
> the CTP board will work reliably, or do I need to go slower...

Slower.  Look for ICD.COM (and companion ICE.COM) which disable the 
internal cache.  I believe you can find a copy of them here:
http://www.oldskool.org/guides/oldonnew/resources/icdice.zip
Also, add wait states if possible.  Fix bus speed at or close to ISA 
standard (see above).

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!)

I used to have programming information on the OB; I don't know where it 
is but I can try to dig it up if you think you'd find it useful.  Also, 
I'm assuming you've seen the treasure trove of info over at 
http://retro.icequake.net/dob/ ?
-- 
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/



More information about the cctech mailing list