Machine organization for multiprogramming

This paper is intended as an introduction to some of the basic concepts of multiprogramming for readers who wish to study the more specialized literature in this field. It attempts to develop a framework for the discussion of multiprogramming which motivates the forms of machine organization used in current multiprogramming systems. The key requirement in multiprogramming systems is that information structures be represented in a hardware-independent form until the moment of execution, rather than being converted to a hardware-dependent form at load time. This requirement leads directly to the concept of hardware-independent virtual address spaces, and to the concept of virtual processors which are linked to physical computer resources through address mapping tables. The structure of the class of hardware-independent virtual processors in the IBM 360 model 67 and GE 645 systems (1), (2), (3), (4), is developed in some detail. Questions of efficiency of throughput in the resulting class of computer systems are considered.