Abstract: A method of operating a computer system to store and retrieve information in a database uses a signature file of the database that is divided into subsets. A word signature is mapped to a particular subset during creation of the file and the same mapping information is used to retrieve the information in response to a query word. Each word signature is a logical word signature and has two components a physical word signature and a subset designation field. In this way, when information is retrieved from the database, only that subset containing the relevant word signature is scanned. The signature file is automatically created by the system as the database is stored on the data storage modules.