Glen W Langdon

Author:

Glen G. Langdon

ISBN #:

0124365507

Author:

Glen G. Langdon

ISBN #:

0960786406

US Patent:

52707121, Dec 14, 1993

Filed:

Apr 2, 1992

Appl. No.:

7/862159

Inventors:

Balakrishna R. Iyer - Mountain View CA
Glen G. Langdon - Aptos CA
Ahmad Zandi - Santa Cruz CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H03M 700

US Classification:

341 50

Abstract:

A method for data compression of records in storage that offers the decoding speed of Variable-to-Fixed codes without loss of sort order characteristics when stored in coded form. The methods include special treatment of the first ordered symbols in both source and decoder alphabets and do not depend on the use of prefix or arithmetic codes for their efficacy. The method saves database storage space by compressing actual records without loss of record sort order characteristics. The lexical ordering or "strong alphabetical" property of the encoding technique are left undisturbed by EOR codes and code-string terminations for byte-padding purposes because both EOR and code-string termination is accomplished with a zero-valued code word. This maintains record order through a proper magnitude relationship between the corresponding encoded records even if one record compresses to a different length than another.