An operating system and a microprogrammable machine

Multiprogrammed interactive operating systems are usually implemented with software. The growth of interest in microprogrammable central processors creates a new dimension in effective computer utilization. While the ability of microprogrammable machines to emulate other machines is well known, the use of microprogramming to aid in the implementation of operating systems is a new area of interest. To investigate this area, a specific operating system and a specific microprogrammable machine were needed. The availability of an INTERDATA Model 4 dictated the choice of machines, but there was not an operating system available for this machine. A model for a multiprogrammed interactive operating system is developed and described. The system is intended for use on a hardware configuration of the general size and capability of the INTERDATA Model 4, but no special consideration is given to its microprogramming characteristics during the development of the system. Selected microprograms are developed to illustrate some implementation features of an emulated machine which has the properties desired by the operating system model. The effect of microprogramming is considered with respect to speed of execution of the resulting system' utilization of primary storage, needs for control storage, and desirability of the use of microprogramming by the independent researcher or systems designer.