System for recording structured read only data table revisions and forming a directory to the latest revisions of table elements

Claim 1

In a data processing device having a first read only memory and a random access memory and output means, a method of retrieving a literal string selected from a plurality of literal strings stored in said first memory comprising the steps of: a) storing a plurality of literal tables in said first memory, each table of said plurality of literal tables comprising: a1) at least one of said literal strings a2) a sequence of string locating data elements, each of said data elements comprising a tag I.D. identifying a literal string comprised in said table and address information for enabling said data processing device to retrieve said identified literal string; and a3) a header, comprising a set of identification parameters for identifying said table, and a revision number, said revision number identifying said table as comprising a particular revision of lateral tables having an identical set of identification parameters. b) assembling a directory of said literal tables, said directory comprising groups of entries corresponding to literal tables having an identical set of identification parameters in said random access memory, said entries being ordered within said groups in accordance with said revision numbers, each of said entries including address information enabling said data processing device to access said corresponding literal tables; c) receiving a request to retrieve a selected literal string, said request including a specified set of identification parameters and a tag I.D. for said selected literal string; d) accessing one of said groups in said directory corresponding to said specified set of identification parameters and accessing an entry in said one group corresponding to the most recent revision of literal tables having said specified set of identification parameters; e) accessing said address information in said entry corresponding to said most recent revision, and then accessing said sequence of string locating data elements for one of said literal tables corresponding to said most recent revision to determine if said selected literal string is comprised in said one of said literal tables; and, f) if so, retrieving said selected literal string for output to said output means; and, g) if said selected literal string is not found repeating steps e through f for the next most recent revision level; and h) if said selected literal string is not found in any of said literal tables corresponding to said set of selected identification parameters, exiting to a predetermine error routine.