STREMA: specifying application processes using streams

A conversational graphic language for application processes is described. It is based on a concept of a stream as the prime building block, which offers a unified treatment of I/O files, subroutines and data base relations. An application process is designed conversationally by linking components belonging to difficult streams. Components are roughly analogous to registers in which each item of flowing data resides whilst it is passing through a given stream. The designer's problem of making provision for handling errors which arise in the generation and transfer of data by I/O and processing subroutines is solved by introducing the construct of constraints.