Using Ada for Discrete Event Simulation

A discrete event simulation library has been written in the Java language, based on the SIM++ library for C++. This allows live simulations to be incorporated into web pages and run remotely. This paper presents a performance comparison with the equivalent C++ simulator and discusses advantages and disadvantages of Java as a simulation language. 1 Motivation The primary purpose of writing simulations in the Java language was to allow \live diagrams" to be incorporated into documents describing the behaviour of computer architectures. Using Java, other people can experiment with a working simulation model by clicking on a web link. This contrasts with using a traditional simulation language written in Simula or C++, where exporting simulation code requires recompilation and installation on each diierent machine. Java incorporates the language features necessary for simulation, notably objects and threads. Current Java implementations compile down to an intermediate byte code, which is interpreted. Thus the main disadvantage of using Java is expected to be longer simulation run times compared with a native C++ compiler. This penalty is quantiied in section 6. SIM++, a discrete event simulation library for C++ written by Jade Simulations Inc 5] has been used for computer architecture simulations as