International Computers Limited

Edward Babb

Vincent D West

An electronic spreadsheet consists of an array of cells into which a user can enter formulas and values. The contents of the spreadsheet cells are translated into a query in a high-level logic language such as the Pure Logic Language (PLL). The query is then re-written according to the rules of the logic language, to produce an answer. The answer is then translated back into formulas and values which can be displayed on the spreadsheet. The system provides a number of facilities not available on conventional electronic spreadsheets: it provides the ability to give generalised answers containing formulas rather than simply numbers, and provides the ability to solve goal-seeking problems, working backwards from a desired result.

Electronic spreadsheet system producing generalized answers including

Hash-coding storage arrangements are known which are capable of storing data values efficiently and permitting rapid testing of whether a given data value is stored. However, such arrangements may produce erroneous outputs. The invention reduces or eliminates these erroneous outputs by providing a further store (which may itself be a hash-coding storage arrangement) which identifies the erroneous outputs, and is used to suppress them.

Hash-coding data storage apparatus with error suppression

A data processing system in which a sequence of records, each record containing data items of various types, is processed. The system is operable in a 'remember' mode in which, if a data item of a particular type is not present in a particular record, the result of the last time that type of data item was processed is used as the result for the current record. This permits data files to be stored in a compressed form in which repeated data items are omitted.

Apparatus for searching compressed data file

A data file searching system in which data is compared with a search key, and the results of the comparison are then analysed by a processing unit. The action of the processing unit is initiated by an end-of-record signal which is generated in accordance with an end-of-record criterion. This criterion can be varied, and this permits the boundaries between records to be effectively varied.

File searching system with variable record boundaries

An information retrieval system in which each record in a file is scanned and a hit signal is produced if it matches a search criterion. The hits are stored in a plurality of bit maps. Each record has an identifying index, which is transformed in a number of different ways to produce addresses for the bit maps. The outputs of the bit maps are combined to produce a stored hit signal. The number of hits is compared with the number of stored hits to determine whether any spurious stored hits have been recorded and, if so, the transformations are modified.

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Stevenage, United Kingdom

Edward Babb