This paper reviews the evolution of process simulation in conjunction with the evolution of computer hardware and software technologies from a chemical engineering perspective. A brief history of this hardware evolution is presented and points to exponential growth of computing power. The current personal computers or full function workstations have at least 1GB of memory, 100GB hard drive and run at 4 GHz. We as chemical engineers can only benefit from this continued hardware evolution, as the personal computer has become our full function slide rule.Concurrent with this hardware evolution there has been a proliferation of operating systems and applications software. Some of the applications software has migrated from mainframes and minicomputers and some has been specifically written to take advantage of the user-friendly features available on today's personal computers. A review of this software is presented with particular emphasis on process simulation software. The currently available fifth generation, non-sequential interactive process simulator does make process modeling and design a truly rewarding experience. This software has been designed to allow the personal computer and the engineer to do what each does best, namely the personal computer performing the systematic number crunching and the engineer the intuitive aspect of process simulation and design. The paper will conclude with a look into the future development of process simulation and its interaction with chemical engineering practice.