All-Magnetic Circuit Techniques

Publisher Summary The great success of magnetic cores in computer memory systems in the early 1950's resulted in a strong desire to incorporate these reliable and inexpensive elements into logic circuits as well. Of special interest was the fact that the bulk of a typical magnetic memory system actually consisted of only the memory cores themselves and interconnecting wires. It was hoped that magnetic logic circuits could similarly be developed in which only cores and wire played the prominent role. For memory, or storage, it is necessary only that the memory cores have proper remanence. For a logic system, however, still other requirements must be met. In particular, it requires power gain in order to overcome inherent losses in the coupling circuits. Thus, in any logic system in which magnetic cores play a prominent role, some cores must be such that each one is capable of driving another core at least as large as it drives. To achieve general logic capability, there are more requirements than for only a shift register (e.g., the ability for one core to drive more than one receiver core, and the ability to mix signals according to different logical combinations). Although core-diode logic circuits have been quite successfully applied, there has been a continuing desire to eliminate all components other than the cores themselves and the interconnecting wires, thus achieving corewire or all-magnetic circuits. All-magnetic circuit technology is currently such that, in many applications, circuits of this type are strongly competitive with the more conventional circuit techniques. In some applications, the advantages of this type of circuit cannot be matched by other techniques. The present status of logic realization with all-magnetic circuitry and the special properties of such circuits are discussed.