[A83] Re: Color Calculators

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: Color Calculators
From: MyOwnLittlWorld@aol.com
Date: Thu, 5 Dec 2002 18:23:19 EST
Reply-To: assembly-83@lists.ticalc.org

In a message dated 12/5/2002 5:24:52 PM Eastern Standard Time, david@acz.org writes:

2) The circumvention requires no modification of any copyrighted
>material. But does require the copying of _two bytes_ of "copyrighted"
>data at a key location.

So...how does it work?

chances are (as far as I can imagine) that the calc processor is required (hardwired) to accept the two bytes on load as it's reading the startup code... If the bytes aren't perfect, the calc's circut won't be complete and it just won't accept power... No, I don't know all that much about circuitry, but it could be accomplished that way I think... Otherwise, the switch would have to be set (and thus able to be changed) in the program... The OS would have to compare the 2 bytes to whatever reference value it had (if not hardwired, the comparison would have to be done in the OS)... Though they could have coded that in many many ways... (short version: if it's searching for FF and CC, then it'll test for both the bytes from a specific rom location, and test those values against whatever it's programmed to test for... If you can change the "copyrighted" values, you could probably change the values it tests for.)