Re: WANTED: Information on Apple II copy protection

[Rubywand <rubywand@swbell.net>]

PetScii writes ...
> 
> Hello!
> I am looking for information on how copy protection worked on Apple II (and
> commodore) disks. If anyone out there has any old information, please pass it
> on!
> I've always been interested in the "dark secrets" of protecting disks!
>

     You name it and it's been tried:

Extra tracks
Recording on half and quarter tracks
Synchronized tracks
Long or short tracks
Non-16-sector formatting
Changed Address and/or Data sector header bytes
Changed GCR byte translation table
Purposefully written bad sectors/blocks
Custom DOS commands
Modified RWTS timing
Custom ProDOS system files
....

     There are stories that one vendor actually punched a hole in their
diskettes so that users who tried to read the holed track would hit the
snag and rip the diskette and/or mess up the drive head(s).


     The best source of protection information and ways to defeat it
would be a collection of Computist issues.

     One famous Cracker, Krackowitz, did a series of informative
articles which may be available in Text files somewhere on the net.

     The Asimov site ( ftp://ftp.apple.asimov.net/pub/apple_II ) has a
decent collection of copiers and other cracking utilities along with
related information.

     The Copy II Plus manual discusses protection methods vis-a-vis
various Copy II Plus features and bit-copy parms.

     There is some discussion of copy protection in Beneath Apple DOS
and Beneath Apple ProDOS.
     


Rubywand