• BASIC;
  • Interpreter;
  • Incremental;
  • Implementation;
  • On-line;
  • Debugging aids


The design and implementation of a conversational BASIC system for ICL 1900 machines is described. The University of Southampton BASIC System (SOBS) is an incremental BASIC interpreter which runs under a variety of operating environments. Fundamental requirement for extensive diagnostic and debugging aids are listed, and their implementation in SOBS is discussed. A brief summary of language features is also incorporated.

The use of SOBS over a number of years has proved its usefulness in the construction of production programs for small- to medium-scale applications as well as in the field of education. A number of enhanced features have gradually been added, and it is to the credit of the original design that the necessary amendments did not significantly alter the initial internal structure of the system.