The design and implementation of a virtual machine operating system

[Kalyan]

The design and implementation of a virtual machine operating system using a Virtual Access Method

ABSTRACT:- In the autumn of 1969, we decided to try a new approach to the design of a virtual machine operating system. Until that time, most installations using Virtual Machine Monitors merely ran operating systems that already existed.

Few, if any, installations had attempted to design and create an operating system that took advantage of its running environment. The Virtual Machine Monitor we were using was a highly modified version of CP-67 which was designed to operate on an IBM S/360 Model 67. Our design motivation centered on the reduction of CP-67 overhead by reducing the amount of virtual memory required to support the operating system.

A secondary design goal was to produce a production oriented system. The resulting operating system should be able to be a particular user's requirements. The design of the New System (NS), as it came to be called, revolved around the fact that it not only knew it was executing within a virtual machine, but took advantage of it. Special communication links were designed and installed allowing NS to more directly control its paging and I/O profile.