Re: frogger disk problem

[fadden@netcom.com (Andy McFadden)]

In article <b07_200001310031@juge.com>,
Jeff Brielmaier <Jeff.Brielmaier@juge.com> wrote:
>The original release of Frogger included a copy protection routine which 
>was incompatible with //e ROMs.  The problem was that Sierra did a 
>checksum on the monitor ROM (an Apple non-no) and the //e ROM 'failed' 
>the check which caused the copy protection to cause a reboot.

Interesting.  I was able to remove the copy protection using a modified ROM
on an Apple II+ (one with a hacked reset routine).  Perhaps they removed
the check from a later release?

I know that the program did compute a checksum, but in the copy I looked at
the purpose was to verify that the checksum didn't change after the program
launched.  This made it so that, if you grabbed an image with one of the
"snapshot" cards, the image would only work on the computer where it was
taken (it factored in other peripherals in the checksum).

At any rate, this would explain why the program would fail even on a
system with Disk ][ drives...

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