dlfrsilver wrote:can you tell about turrican atari ST protection used?
Turrican also has a combination of two, or three if you want, protections. But the one I’m referring is, in some senses, the most advanced floppy copy protection that I know.
I’ve seen it so far in about a couple of dozen titles. Some examples with this protection, with a couple of variations: Dizzy Treasure Island, Ghostbusters II, Ghost & Goblins, F-29, Death Trap (and several other Anco titles), etc.
It is quite complicated and long to describe the details, and some technical background is required to understand it. It has no relation to any other type of protection. Let’s say that it consists on an area of the disk surface being erased.
This is the only “non-physical” (no physical alteration of the disk surface) protection that defeats hardware copiers such as the Discovery Cartridge (and yet it can be duplicated).
It is sometimes possible to make working copies of this protection (some people succeeded with analog copiers after many retries). But after examining the copy the protection was not actually copied. So it seems that some variations of the software protection is buggy.