ANSI
X3.241-1994
American National Standard
for Information Systems –
Data Compression Method –
Adaptive Coding with Sliding Window
for Information Interchange
Secretariat
Computer and Business Equipment Manufacturers Association
Approved August 30, 1994
American National Standards Institute, Inc.
®
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Contents
Page
Foreword..................................................................................................ii
1 Scope and conformance ....................................................................1
2 Normative references.........................................................................1
3 Definitions.........................................................................................1
4 Algorithm identifier.............................................................................1
5 Data format .......................................................................................2
Annexes
A Encoding overview.............................................................................5
B Example compression encoding method.............................................8
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Foreword (This foreword is not part of American National Standard X3.241-1994.)
This standard specifies a lossless data compression method that is intended
for general purposes. It contains features that make it particularly applicable
to systems for recording information on interchangeable media.
This standard was developed by Technical Committee X3B5, by X3 project
882. The first draft was produced in November 1991. The second draft was
produced in March 1992.
There are two annexes in this standard. Both are informative and are not
considered part of this standard.
Requests for interpretation, suggestions for improvement or addenda, or
defect reports are welcome. They should be sent to the X3 Secretariat,
Computer and Business Equipment Manufacturers Association, 1250 Eye
Street NW, Suite 200, Washington, DC 20005.
This standard was processed and approved for submittal to ANSI by the
Accredited Standards Committee on Information Processing Systems, X3.
Committee approval of this standard does not necessarily imply that all
committee members voted for its approval. At the time it approved this
standard, the X3 Committee had the following members:
James D. Converse, Chair
Donald C. Loughry, Vice-Chair
Joanne Flanagan, Secretary
Organization Represented Name of Representative
American Nuclear Society..................................................Geraldine C. Main
Sally Hartzell (Alt.)
AMP, Inc............................................................................Edward Kelly
Charles Brill (Alt.)
Apple Computer, Inc. .........................................................Karen Higginbottom
David K. Michael (Alt.)
AT&T Global Information Systems......................................Robert K. Kramer
Thomas F. Frost (Alt.)
Bull HN Information Systems, Inc.......................................William George, Jr.
Compaq Computers ...........................................................Ed Olkkola
Digital Equipment Corporation............................................Scott K. Jameson
Richard Hovey (Alt.)
Eastman Kodak Company..................................................James Converse
Michael Nier (Alt.)
Guide International, Inc......................................................Frank Kirshenbaum
Tony Gualtieri (Alt.)
Hewlett-Packard ................................................................Donald C. Loughry
Hitachi America, Ltd...........................................................John Neumann
Kei Yamashita (Alt.)
Hughes Aircraft Company ..................................................Harold Zebrack
IBM Corporation ................................................................Joel Urman
Mary Anne Lawler (Alt.)
Institute for Certification of Computer
Professionals (ICCP) .......................................................Kenneth Zemrowski
National Communications Systems ....................................Dennis Bodson
Granger Kelley (Alt.)
National Institute of Standards and Technology..................Michael Hogan
James H. Burrows (Alt.)
Neville & Associates ..........................................................Carlton Neville
Northern Telecom, Inc. ......................................................Mel Woinsky
Subhash Patel (Alt.)
Recognition Technology Users Association ........................Herbert P. Schantz
Gerald Farmer (Alt.)
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Share, Inc..........................................................................Gary Ainsworth
David Thewlis (Alt.)
Sony Corporation...............................................................Michael Deese
Storage Technology Corporation........................................Joseph S. Zajaczkowski
Samuel D. Cheatham (Alt.)
Sun Microsystems, Inc.......................................................Gary S. Robinson
Sybase, Inc........................................................................Donald R. Deutsch
Texas Instruments, Inc.......................................................Clyde Camp
Fritz Whittington (Alt.)
3M Company .....................................................................Eddie T. Morioka
Paul D. Jahnke (Alt.)
Unisys Corporation ............................................................John Hill
Stephen P. Oksala (Alt.)
U.S. Department of Defense ..............................................William Rinehuls
C. J. Pasquariello (Alt.)
U.S. Department of Energy ................................................Alton Cox
Neil S. Jarrett (Alt.)
U.S. General Services Administration.................................Patrick Plunkett
Douglas Arai
Wintergreen Information Services ......................................Jack L. Wheeler
Xerox Corporation..............................................................Roy Pierce
William Ted Smith (Alt.)
At the time is approved this standard, Technical Committee X3B5 on
Digital Magnetic Tape, which developed this standard, had the following
members:
Richard T. Steinbrenner, Chair
Samuel D. Cheatham, Vice-Chair
Bruce H. Anderson
Leonard Badour
Peter Bramhall
James T. Craze
Richard D’Ambrise
Mike Deese
Gary R. Early
Howard Flagg
Arthur Freeman
Michael Galata
Michael L. Helsel
Hakan Hemdal
David M. Hudson
Norris Huse
Don Jeffares
Kyriacos Joannou
Clayton Johnson
W. D. Kessler
Randy Kerns
Bill R. King
Robert Lutz
Jack L. Maynard
David McFarland
William Mealey
Bill Medlinski
Eddie T. Morioka
John Neumann
Gerrit Nijssen
Ed Rhodes
Cam Schweitzer
James V. Tierney, III
Charles Wellington
David M. Wilson
Kirk D. Wilson
James W. Wolf
Joseph Zajaczkowski
David Berry (Alt.)
Michael L. Bolt (Alt.)
Anthony B. Bova (Alt.)
Jeff Bratt (Alt.)
James U. Chesnutt (Alt.)
James Chu (Alt.)
Richard F. Davis (Alt.)
Louis C. Domshy (Alt.)
David J. Donald (Alt.)
Larry P. Dunn (Alt.)
James Eggebeen (Alt.)
Darryl Feterl (Alt.)
John Fleming (Alt.)
Lonnie Ford (Alt.)
Ren Franse (Alt.)
Shoji Fujiwara (Alt.)
Jerry Ganske (Alt.)
John Geogehan (Alt.)
Kunio Goto (Alt.)
Dan Hallock (Alt.)
Ed Hauck (Alt.)
Matthew F. Jacobs (Alt.)
Paul D. Jahnke (Alt.)
Tony Jasionowski (Alt.)
Clarence Jones (Alt.)
Ali Khorsandian (Alt.)
George Klechefski (Alt.)
Steve Krupa (Alt.)
Carl Labmeier (Alt.)
Demetrios Lignos (Alt.)
Al Lun (Alt.)
George McBride (Alt.)
T. McCarthy (Alt.)
Charles B. Meyer (Alt.)
David R. Mills (Alt.)
Tom Molstad (Alt.)
Robert Monsour (Alt.)
Donald E. Morgan (Alt.)
Kenneth G. Neimiller (Alt.)
Roy Nelson (Alt.)
Kentaro Odaka (Alt.)
Mark OkaFuji (Alt.)
Terry L. Parsons (Alt.)
Pete Passaretti (Alt.)
Bob Richmond (Alt.)
Michael H. Riddle (Alt.)
John C. Shovic (Alt.)
Richard Silva (Alt.)
Leif Skaar (Alt.)
Mitchell Steinberg (Alt.)
Jun Takayama (Alt.)
Gerald Taylor (Alt.)
Joseph Trost (Alt.)
Richard Woo (Alt.)
Kei Yamashita (Alt.)
Organization Represented Name of Representative