Virtual Window Systems: A New Approach to Supporting Concurrent Heterogeneous Windowing Systems

A "virtual window systeml" (VWS) is a simple model of a window system which can be used to host other more sophisticated window systems. The VWS allows the window systems to share the physical display in a controlled fashion. A VWS is analogous to the virtual machine monitor (VMM) [MadnickT4] concept in operating systems, where a single physical computer can run multiple operating systems, each in its own protection domain. Unlike the VMM concept, the window systems supported by the VWS need close cooperation to perform tasks, such as cut and paste between windows of different window systems.

This paper describes the VWS concept, discusses an architecture for a VWS, describes limitations of the VWS concept, discusses some lessons learned from the design and implementation of our prototype, and describes the use of WVSs for various application domains.