The EXPOSER system and fault diagnosis

A local firm manufactures a range of electronic banking equipment (terminals). For any particular piece of equipment a standard sequence of tests is carried out on the completed item before it is shipped to the customer. If any of these is failed then diagnostic action is taken, normally taking the form of `module substitution´, to determine the faulty module. In the case of a faulty item repair is carried out (usually module replacement) and it is resubmitted for testing. The company wanted assembly line workers rather than engineers to be able to carry out these test and diagnosis procedures. It was felt that a PC based system to guide such personnel through these procedures would be appropriate. EXPOSER (expert on the origin of system errors) was written in an attempt to fill this need. EXPOSER is written in PROLOG to run an IBM PC with a minimum of 640 K of RAM