GB1472056A - Information storage systems and input stages therefor - Google Patents

Abstract

1472056 Data processing systems BRITISH FOOD MFG INDUSTRIES RESEARCH ASSOCIATION 18 April 1974 [24 April 1973] 19300/73 Heading G4A A storage location is addressed by an address consisting of a pair of keywords uniquely identifying the location. The address has the sequential format "keyword, space word, key word, end word". A logic circuit rejects any address not having this format. The space word and end word are the same for each address. In the embodiment described the address is keyed in to a store and displayed on a c.r.t. A pointer on the display points to the first word, which is automatically passed to comparators which respectively detect character, space, and end words. An additional comparator may be used to detect a termination word which terminates a sequence of addresses which relate to the same information item. If none of these words is detected or if the keyword is one of a number of forbidden keywords the circuit gives a reject signal. If the first word is a permitted keyword a bi-stable is set and the pointer advanced to the second word. If this is found to be the space word and if the preceding word was a keyword another bi-stable is set and the first reset, otherwise a reject signal is given. The pointer now advances to the third word and so on. If the format is correct the relevant location is addressed. The address may be stored together with the information item or alternatively may be stored with a serial number in an address store, the information item being stored with the same serial number in an information store. The circuit may be modified to recognize addresses having only a single keyword followed by an end word.