Content Addressing by Software

This chapter contains a review of certain programmed searching methods which might properly be called associative or content-addressable, because an entry (record, document, file, associated word or data, etc.) can be accessed directly on the basis of a keyword or a specified part of the entry. It is to be noted that all of these methods are connected with the use of generalpurpose computers, and the entries are thereby stored in standard randomaccess (addressable) memories. The methods described in Sects. 2.2–7 are generally known under the name hash coding. Al ternative names used for the same techniques are hashing, hash addressing, hash-table method, scatter-storage techniques, key trans formation, key-to-addresstrans formation, computed-entry table method, randomization, random addressing, scrambling, direct-access method, and possibly others. Another content-addressable organization of data named TRIE is described in Sect. 2.8.