Re: Copy protection schemes on the PET

From: Larry Anderson (
Date: 2000-09-26 17:24:13

>This brings a question to my mind.  What kinds of copy protection were
>used on the PET?  Were ROM chips and cassette port dongles the only ways,
>or were disk errors used as well?
>	Marko
I didn't see a disk error protection till I saw Frogger for the 64.  The high-end
of PET protection was EPROM which was used by many business software packages
like WordPro, Delphi's Oracle, Paperclip, VisiCalc, etc.  Though the problem
is if you had two or three of these programs and you only have one ROM you need
a ROM switcher or a RAM/ROM board (RAM loadable emulates ROM with a switch).
 Cassette Dongles were the next one, programs like PETSpeed used that.

After that there were other ways, especially for cassette based software such
as putting an RTS or small ML in the 2nd cassette buffer and saving the program
starting there, so when someone makes a copy with a BASIC SAVE it would not
function.  The most ingenious one I saw was for Flash Attack, they put some
data in the 1st casette buffer and then saved the program using the second cassette,
took me and my brother a while to figure that out.

There also was some auto run thing you could accomplish on cassette programs
(keyboard buffer?) but was easily circumvented.

I don't recall much manual protection either.  Some programs were serialized
and you had to order them direct.
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