CHiPS is a package for the synthesis of complete heat-integrated processes. Based on a fully user extensible unit model library, using discrete programming techniques, the package can handle a large variety of problems and will generate processes using distillation units, reactors, flash units, absorbers, etc. Flowsheets generated can include recycle and makeup streams. The program has been written in the C and Fortran languages and is portable across a variety of machines : CHiPS runs on single workstations, on workstation clusters, and on distributed memory multicomputers. This paper outlines the main features of the package, including the following : single pass generation of heat integrated processes, processes are generated allowing for the effect of unit operating conditions on down-stream units, the N best solutions are found, instead of just the "optimal" flowsheet, for any value of N, a unit model interface is defined, which allows a user to write new unit models and easily add them to the basic package, and the epee interface is available for use within a distributed process engineering environment. We describe briefly some of the critical implementation issues relating to memory and computer time restrictions imposed by the requirements of an interactive computer aided design environment. We discuss how sparse memory techniques enable the package to run in low memory conditions whilst still allowing efficient re-use of repeated computations, and how parallel implementations allow us to increase the complexity of the models used whilst still generating results in reasonable amounts of time.