Communication Network Software Analysis.

摘要

Synchronous (or simultaneous) program execution (SPE) is a technique that allows the same program to run synchronously on geographically separated computers. However, the results generated appear to the user at the different sites as if the users are sitting in front of the same computer. The difference between the SPE technique and the distributed systems techniques is that with the SPE technique the same execution takes place at each computer, while with distributed systems techniques, parts of one program execute on different computers. The SPE technique can be used in reducing communications in cases such as computer conferencing. The SPE technique is based on the creation of a Shell running at each computer and the transmission of messages between the Shells. Only a low bandwidth line connects the computer systems. The Shell is constructed at each computer system, in software, and resides between the operating system and the executing program and between the entering inputs and the operating systems. This paper presents and analyzes Petri nets that model the synchronization of simultaneous program execution between two computers. The analysis of the Petri nets indicates proper operation of the system.