A Minicomputer Retrieval System with Automatic Root Finding and Roling Facilities Available to Purchase

Since 1965, a feature card index has formed an essential component in answering technical enquiries. It now contains over 20 000 items. By 1973 the Mathatron Desk‐Top computer used to process the paper tape output from an automatic testing machine had become obsolete. It was decided that the replacement should handle the retrieval system input as well as meeting the general needs for scientific calculating. The machine selected was a Varian 620L: a £12 000 machine with 12–16K core and disc storage. Although the basic notion of an inverted file has been retained, a number of novel automatic features have been incorporated. These include the reduction of index entries (which may be compounds) to their singular root forms, the elimination of redundant words and the auto‐roling of words through their morphology. Some measure of heuristic performance is sought in this process. The system can easily contain the entire index to date on a single interchangeable disc and it is expected that subsequent discs will contain at least 3–4 years information.