A Survey of the Status of Microprogramming

Abstract

Microprogramming is one of the most influential concepts in shaping the development of modern digital computer systems. With the implementation of microprogrammed stored logic as the control logic for computers, the system designers’ restrictions have been replaced with fantastic possibilities. Microprogramming has provided the major motivation into the research for computer compatability, design flexibility, automated diagnostics, and, more recently, microprogramming of the “writable” control logic by the users. It should also receive credit for the successful design of general purpose and multiple purpose computers. The many possible uses of microprogramming are the subjects of research for system programmers and designers. The growing popularity of the art is stimulated by the research and development of fast, compact, nondestructive read-only memory (ROM) and writable (read/write) memory. For the reader who is not familiar with the term “microprogramming” and the concepts behind it, the appropriate question is: What is microprogramming? To answer this question, we will introduce the basic concepts of microprogramming in this section and then compare conventional implementations with microprogrammed implementations.