More Amiga Descriptors (Disk Formats)

19 April 2002

Descriptor for Digital Magic software games. It is a rather ambiguous one, a modified Rainbird format and actually only took a few minutes to derive, which is probably the same amount of time it took to “develop” (nick?) from Rainbird.

Games known:

• Escape from Colditz
• Fly Fighter
• (as always - probably more)

Firstly a refresher about Copylock. This is a really sophisticated protection scheme that it is practically uncopyable without quality loss. Hence a first generation hardware copy may work (though it is more likely to fail). However the protection check is normally applied to the final masters rather than integrated during development, and so it was very easy to remove by crackers.

Maybe to address this issue, Rob Northen’s disk format “PDOS” is a Encrypted Disk Format that is written on long tracks. The good point from our point of view is that it is a normal, but 12 sector format originally made on a normal density disk (probably by the developer) which was then written onto long tracks (probably by Rob). There is a field in the descriptor that specifies the size of the inter sector gap (gap size until next sector) and the loader can definitely still read it if you change it to a value during remastering that will make fit onto normal tracks. Obviously PDOS is a post process format too.

As with all of these types of protections, a fully authentic copy will be written if the necessary hardware is available.

All the details will be posted when we are finished.