In recent years, it has gradually become popular to use discrete-event simulation as a tool for analyzing the hardware architecture of shared-memory multi-processors. A complete and detailed machine simulation environment can be utilized to evaluate the performance of a completed prototype hardware architecture in an operating system and application software. This paper describes the development, operation, and future development of a parallel machine simulation environment which has the ability to execute programs. At present, a shared-memory multiprocessor simulator has been developed that can execute 80x86 programs. On the other hand, we have focused on parallel discrete-event simulation to reduce the simulation time. The simulator works through Ethernet to connect multiple workstations to solve problems. Some workstations are used for calculations while the others are used for memory management. Thus, it is easy to get a parallel machine simulation environment. This simulator can provide an environment which can be used to execute application programs, and to simulate different system architectures by adjusting parameters. In addition it can calculate the run time for an application program so as to evaluate the possibility of executing the application program in a real system. The source code for the simulator can be downloaded from ftp://loon.cs.tku.edu.tw/pub/86sim.tgz.