This thesis describes the design and development of high level language programming systems for use on a small mini-computer installation in an educational environment. Any high level language may be implemented in a number of different ways. The major alternatives are reviewed with particular reference to hardware resources, ease of use and the need to cater for both on-line and off-line applications. The implementation of a programming system based upon the use of an interpreter rather than a compiler is described. The system enables a single user to create develop and execute programs for applications involving on-line data acquisition and control. Hardware resources are most effectively utilized in a time shared rather than a dedicated mode. The problems of extending this system to permit time sharing are discussed and an appropriate solution is described. In a situation where it is necessary to segregate data processing from data acquisition, the use of a common programming system is desirable. An off-line operating system is described which adds file handling capabilities to the interpreter and provides a common software interface between data acquisition and data processing programs.