Importance

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Abstract

A digital computer system has a central processor unit (CPU). A computer program, entered into the digital computer system for execution thereof, has a program code word embedded at an arbitrary location therein. An addressable programmable array of logic (PAL) is operatively connected to the CPU for receiving a READ signal originated by the CPU at the address of the PAL, the PAL being programmed to output a portion of a preset array code word in a response to the READ signal, and to output the remainder of the array code word in segments in response to subsequent READ signals at the same address. A data bus, connected to receive and transmit the portion and remainders of the array code word to the CPU for comparison with the program code word. The program code word and the array code word are compared and, if identical permit use of the program and do not permit use when the program code word and the array code word are not identical.

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First Claim