A method for controlling usage of a programmable computing machine which operates in accordance with uncoded or published machine language operation codes including uniquely encoding the uncoded operation codes of instructions of a program to be used on the computing machine as a function of location...http://www.google.fr/patents/US4246638?utm_source=gb-gplus-shareBrevet US4246638 - Method and apparatus for controlling usage of a programmable computing machine
Method and apparatus for controlling usage of a programmable computing machine
