A recursive virtual machine architecture

Abstract

This paper summarizes the preliminary design of a computer system with a recursive, virtual machine architecture and gives a brief account of the considerations leading to that design . In this system, each process operates in its own address space, called its virtual memory, and can create other processes within its space and pass control to them. The newly create d processes can, recursively, create their own descendants without the knowledge or assistance of a supervisor. There is no “privileged” or “supervisor” state; protection is provided entirely by the virtual memory mechanism, and each interrupt is directed by hardware to the process designated to handle it. Virtual memories are segmented; moreover, paging is treated as a recursive application of segmentation and can occur at any level. The machine architecture encourages modular and hierarchical approaches to program design because of the high degree of protection afforded by the creation of new virtual memories at low cost.