Penetrating an operating system: a study of VM/370 integrity

The virtual machine architecture embodied in wm/370 greatly simplifies an operating system in most areas and hence increases the probability of correct implementation and resistance to penetration. The control program is not concerned with user files or multiple access methods. It simulates a machine with a fixed number of buttons and instructions that require interpretation. The choice of System/370 Principles of Operation as a user interface provides a well understood and well documented interface. The result is a system that is smaller and simpler, with fewer opportunities for error. The simplicity enhances the probability of obtaining security. The exception area is the support of input/output.