ENSEMBLE is a programmming system for writing concurrent programs on a personal computer (PC).ENSEMBLE consists of a library of Turbo Pascal¹ units to be used with applications written in the same language and executable on IBM PCs or compatibles under the MS-DOS² operating system. ENSEMBLE provides the programmer with a set of facilities and predefined abstractions that simplify the construction of concurrent programs. The main abstractions are coroutines and tasks.ENSEMBLE's main goal is to provide an environment that can be easily used by students for gaining experience in a wide variety of concurrent programming models and techniques. However, ENSEMBLE was designed to be also a satisfactory production tool for writing concurrent and real-time software on a PC.