The Virtual Environment Operating Shell (veos) was developed at University of Washington's Human Interface Technology Laboratory as software infrastructure for the lab's research in virtual environments. veos was designed from scratch to provide a comprehensive and unified management facility to support generation of, interaction with, and maintenance of virtual environments. VEOS emphasizes rapid prototyping, heterogeneous distributed computing, and portability. We discuss the design, philosophy and implementation of veos in depth. Within the Kernel, the shared database transformations are pattern-directed, communications are asynchronous, and the programmer's interface is LISP. An entity-based metaphor extends object-oriented programming to systems-oriented programming. Entities provide first-class environments and biological programming constructs such as perceive, react, and persist. The organization, structure, and programming of entities are discussed in detail. The article concludes with a description of the applications that have contributed to the iterative refinement of the VEOS software.
Utilizing object-oriented databases for concurrency control in virtual environments
