Magnetic Core Circuits for Digital Data-Processing Systems

A magnetic core has a switching time of a few microseconds and has the ability to store binary information indefinitely without application of power. New techniques for using cores in digital data-processing systems are described. Reference is made to a system containing eight hundred cores to indicate reliability, and size and power requirements relative to a vacuum tube version. Three fundamental interconnecting circuits for data transfer are described. These are the single-diode loop, and a new split winding loop, and new inhibit loop. The single-diode loop permits unconditional transfer of information from one or more transmitting cores to one or more receiving cores. The split-winding loop allows conditional transfer between cores and thus permits logical operations upon isolated cores. The inhibit loop offers a reliable method for conditionally inhibiting the transfer of information from one core to another. A logical symbolism for these loops has been found useful in system design and analysis. Units performing the functions of storage, control, and logic are explained. These are shift registers (serial, parallel, and reversible); cycle distributors and counters; negation, inclusive- or, conjunction, exclusive- or, and material equivalence (compare). System design considerations are illustrated by two examples of half-adders.