Re: Copy Protection of PET cassettes - Flash Attack.

From: Marko Mäkelä <>
Date: Mon, 9 Aug 2010 21:52:49 +0300
Message-ID: <20100809185249.GA2904@x60s>
On Mon, Aug 09, 2010 at 01:16:31PM -0500, MikeS wrote:
>I notice you skip over the part about finding the start and end 
>addresses... ;-)

When I transferred some tapes several years ago, I dumped them to 
low-level images (.tap) format with mtap or TAPir and loaded them in 
VICE, setting breakpoints in the KERNAL code as needed. It is convenient 
to work in that way, enabling "warp speed" to cut loading times and 
starting over and over again as needed :-)

Best regards,


PS: If you can produce a .tap image of the game, I am willing to take 
the challenge and document the steps that I took.

PPS: I have sometimes found watchpoints (memory read/write traps) useful 
when debugging this kind of problems.

PPPS: I wonder if the VICE guys have ever thought about implementing 
something similar to Valgrind Memchecker to catch access to 
uninitialized or unaddressible memory. For example, some Vic-20 
cartridges seem to expect that RAM is initialized in a certain way.  
Cosmic Cruncher springs to my mind.

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Received on 2010-08-09 19:00:31

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