Method of using signature subsets for indexing a textual database

A method of operating a computer system for storing and retrieving information in a database, said computer system having a processor, a memory with address lines and a FIFO buffer, said processor having an input section, an output section and a control, said method comprising the steps of:

• (i) storing the database in the data storage means;
• (ii) during loading of the database, said system automatically creating for the database a signature file which is divided into subsets, mapping a word signature to a particular subset during creation of the file and storing said signature file subsets on said data storage means;
• (iii) during retrieving, after the signature file is created, entering at least one query word into the system;
• (iv) said system automatically creating a signature for each query word entered into the system;
• (v) in response to a query word, said input section receiving information from said data storage means, said control reviewing said information and sending all word signatures to said address lines of said memory, said memory providing information to the control to enable it to determine whether a particular word signature in the input section matches a signature for said query word if a match occurs,
• (a) the control sending the word signature to said FIFO buffer, the control remembering that a match has occurred and sending the document identifier located subsequent to the matched word signature to the FIFO buffer, the control then moving on to process the next word signature received from the data storage means and so on;
• if there is no match,
• (b) the control ignoring the word signature and moving on to process the next signature word received from the data storage means and so on;
• the control thereby effectively being capable of processing several query words in parallel.