Questions about Central Point Deluxe Option board

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Thu Jun 27 12:43:47 2002

> > On a bet, once, I made a disk from which a usable copy could be made with
> > DISKCOPY on a stock 5150, but that the option board, with it's software,
> > could not copy.
> > Hint: it had problems with DISKCOPY when using Teac drives.

On Thu, 27 Jun 2002, Sellam Ismail wrote:
> Details, please.

No guesses or ideas?
Or is it a subject for which nobody but Sellam gives a shit?



Very simply:
The option board software is completely dependent on the index pulse. No
index pulse; no read (crash with some versions!)

Format a disk normally, then block the index hole (either by covering it,
or removing the disk from its cover and reinstalling it with the cover
reversed). Put a disk label on the backside, so that the user knows which
way to put the disk in.
Now the disk is still readable by DOS, and even DISKCOPY, but the option
board software chokes.

"But the user could just uncover the hole, or punch a new one (Using the
XenoSoft (formerly Berkeley Microcomputer) Flip-Jig (tm))"
So, ...
modify a drive to index off of the spindle, instead of the index
photocell. While you're at it, jumper it to not need a write protect
notch.
Format the disk (upside down) and use it normally.
DOS and DISKCOPY are perfectly happy with it, even with a
"normal" drive. (But most errors that could occur will be misreported as
err code 128: "drive not ready".)
But, unless the user makes a comparable mod to their drive, the
option board software chokes.
And, just to make sure that punching a hole doesn't work: use a hard
sectored disk! When upside down, no index holes show. The modified drive
will not see any, and will index off of the spindle.
Stock drives will see no holes, which will not bother DOS (for READING),
but will frustrate the option board software. If the user punches a hole,
then instead of getting an index hole, he gets TEN index holes, which will
also discombobulate the option board software (and DOS).


But, ...
TEAC drives (and probably some others) wouldn't work with the technique,
since they look for drive up to speed by monitoring the index pulse.
Received on Thu Jun 27 2002 - 12:43:47 BST

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