The Special Issue on High-Speed Memories

ABOUT THIS ISSUE the promises long heralded for thin-film memories are D URING the last few years, rapid advancement on the threshold of being fulfilled in operating equip-has occurred in the introduction and use of ment in the field sophisticated digital computing systems. A key System-oriented approaches to computing appjica-element of this progress has been the development of tions have resulted in the emergence of a variety of spe-high performance internal memories. The demand for cial purpose memories: read-only, associative, very-improved computing capability has increased in an high-speed control and scratchpad memories. Direct ac-exponential fashion as computer utilization spread into cess mass memories show promise of being competitive, commercial, military, and industrial applications. As a on a cost-performance basis, in those applications result, a need has been created for memories with per-usually reserved for disk and drum. Based on a new formance levels considered impossible a few years ago. organization, the 22D, these are in various stages of de-Traditional approaches have been supplemented by velopment or are in actual use in production equipment. new techniques made possible by advances in the ma-This period of time is an exciting one for those of us terials sciences. The resulting new devices have been engaged in the memory field. It is a time when new utilized by memory developers to mechanize and to techniques evolving from the laboratory promise im-organize memories which offer the systems engineer proved performance, perhaps by an order of magnitude new levels of performance (increased speed, larger or more. We have been able to participate in and ob-capacity, and lower cost). serve the evolution of these techniques from concept For many years, the ferrite core has figured domi-to working hardware. There is still much to be accom-nantly in the fabrication of internal memories. Only plished. recently has this dominance been challenged. In fact, As the requirements for higher and higher volume of the majority of computers in operation today use ferrite direct access storage increase, it appears that the pro-core memories as the high-speed internal store. In the duction of memories from discrete storage elements last year, however, we have seen delivery of thin-film will become economically infeasible. Consequently, new memories in various forms, operating in systems that methods of mass and batch fabrication will be required might otherwise have utilized core memories. Many of to render these systems economically possible.