Hmmm... Read below direct snippet. www.guardsoft.com

"Our Mission

Guardsoft is committed to improving software quality through the use of a new debugging and testing technology called Relative Debugging.

Relative debugging allows a user to compare data between two executing programs. It was devised to aid the testing and debugging of programs that are either modified in some way, or are ported to other computer platforms. Whilst traditional debuggers force the programmer to understand the expected state and internal operation of a program, relative debugging makes it possible to trace errors by comparing the contents of data structures between programs at run time. In this way, the programmer is less concerned with the actual state of the program, and more concerned with finding when and where differences between the old and new codes occur"

Maybe used for random data usage packers/encryptors?

Have Phun.