On 5/18/2019 2:34 PM, Marko Mäkelä wrote: > On Fri, May 17, 2019 at 08:43:13PM -0500, Jim Brain wrote: >> Given Pete's response about putting a JD ROM in and the thing >> refusing to work, does anyone on list have the drive and would be >> willing to test? > > Could it be that some address or data lines have been swapped on the > circuit board? In that case, you would have to transform the EPROM > image accordingly. It should be rather easy to figure out the mapping > by examining the raw image of the original ROM. > > It is an interesting idea that permuting some instructions would > thwart copyright claims. I wonder if that would really have held up in > court. Even back in that day, there had been some disputes, such as > one between Commodore and Bally Midway, regarding Radar Rat Race aka > Vic Rat Race aka Rally-X. > > Marko > I don't think it's an issue with BlueChip ROM, as no address or data lines are swapped. The FSD-1 had a data line swapped (D3/D4, as I recall). I doubt seriously it would stand up to copyright claims, as the correct code can be pulled from the bus during operation, which would shew the correct code. -- Jim Brain brain_at_jbrain.com www.jbrain.comReceived on 2020-05-29 22:03:13
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