Computer system for preventing copying of program from a storage medium by modifying the program using a unique key

Claim 1

A computer system having a central processing unit, an internal memory and an external storage including a storage medium, said computer system comprising: means for determining if a program on said storage medium has been accessed a first time; first accessing means, coupled to said determining means, for reading a program from storage medium into said internal memory when said determining means determines that said program is being accessed for the first time, said first accessing means including program supplier means for reading information from said storage medium that is in a special storage format; first means for storing a unique key set of said computer system; program modifying means, coupled to said internal memory and to said first means, for modifying the program read from said storage medium by said first accessing means and stored in said internal memory based on said unique key set, said program modifying means including means for determining when said first accessing means has operated, and means for activating said program modifying means once an operation of said first accessing means has been detected by said determining means; program writing means, coupled to said internal memory, for writing the program modified by said program modifying means in the storage medium in a standard storage format; and standard program loading means for reading said program from said storage medium of said external storage in said standard format after said determining means determines that said storage medium storing the program have been first accessed, said standard program loading means reading said program in said standard storage format and being incapable of reading said program in said special storage format.