Why do people keep stealing my work :(

der Mouse wrote: It is *very* hard to design these sorts of checks. First, you need to make sure that they are totally ineffectual while you are developing the "real" code. (you don't want to waste your time tracking down a bug that isn't really there!) Second, you need to make them hard to detect. Simple checksums during POST (etc.) take just a few minutes to find and patch around. Even continuously running checks are easy to spot unless they look like they are doing "real work" ("Gee, why is this piece of code just walking through memory...?") Third, they need to be subtle in how they affect the normal play of the game when they trigger -- if it is to noticeable, then it is too easy to see when they have kicked in. Just like adding arbitrary 3 second delays to failed login attempts, you want to make the counterfeiter have to invest a lot of time *deciding* if he has beat the check system or not. Fourth, when you "install them", you need to be "Ivory Soap Sure" that they work properly -- in a legitimate game as well as in a hacked game! All in a machine that is a fraction of a MIPS :> Unfortunately, there never was a good solution to this problem. Software hacks like these are labor intensive. And, in a market (at that time) where time to market was *critical*, "wasting" a week writing/debugging/installing them was expensive. Yet, hardware protection schemes were just as easy to beat (even easier in today's technology!). Some of the schemes that came along were quite imaginative. But, also quite costly to implement (for a machine that went to the end purchaser for < ~$2000). [IIRC, the vector engine in Tempest was pretty much "fully disclosed" in their documentation -- this wasn't the case in all machines (though Atari used LOTS of "custom chips" in their machines)]