1. A method of extending the addressing capability of a computer to a larger memory capacity than the inherent operand portion of the instructions of the computer without affecting hardware and software logic and with no additional instructions or controllers, the steps comprising: a. providing a high-speed magnetic core memory having the desired capacity of memory; b. extending the memory address register to directly address the higher capacity memory; c. extending the program instruction register to directly address the higher capacity memory; d. extending the index registers to create an extended data address register for directly addressing the higher capacity memory; and e. providing a no-index register reference to create an extended data address register for addressing said higher capacity memory.