Abstract: Digitally encoded data such as classified advertising and other data bases of similarly related messages are broadcast on a serial-type digital data transmission system. Each message is preceded by a headnote, structured so that upon reception, the receiver can select messages based upon a combination of hierarchical and relational views of the message data, without any interaction whatsoever with the broadcast system."Hierarchical access" means that messages are considered in categories and sub-categories. "Relational access" means that within sub-categories access is possible by a combination of attributes or keywords (i.e. using "and", "or", and "not" to combine multiple key phrases).We call the invention ReQueSt-DB. The name is derived from "Relational Queries on Sequential Data Bases". ReQueSt-DB allows rapid and facile access to one-way, cyclically broadcast, bit serial, sequential data bases consisting of (possibly) many thousands of messages with high selectivity.

Abstract: A machine-implemented process, and apparatus, for performing a set membership test on large sets through the technique of binary hash coding with a known allowable expectation of an error. The present invention does not employ content addressable memory; rather, the present invention performs set membership testing by utilizing a hash function, which produces a randomized plurality of simple address locations within a bulk memory, for each item in the set. A testing for membership comprises employing a logical AND operation upon all values of binary indicators at memory locations addressed by hash values of a test item, to determine whether each and every hash value generated for the test item exactly matches with previously loaded indicators at those address locations in the bulk memory, which in the pereferred embodiment is of the CCD type. The present invention is a machine-implemented process, and employs a known algorithm as part of the overall process.