Neil P Maclean

US Patent:

50972618, Mar 17, 1992

Filed:

Nov 19, 1990

Appl. No.:

7/615665

Inventors:

Glen G. Langdon - San Jose CA
Neil H. MacLean - Tucson AZ
Robert W. Miller - Tucson AZ
Mayank R. Patel - Tucson AZ

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H03M 730

US Classification:

341 51

Abstract:

A tape drive system includes a compaction scheme whereby the data to be stored on the media is encoded and formatted to take less space along the tape length. The data to be written to tape is placed into equal byte lengths or sets. The sets of data are directed to a plurality of encoders in turn and compacted through an Arithmetic Binary Coding program having two statistic tables per encoder to allow format compatibility with a higher throughput compaction scheme. The compacted sets are sequenced and formed into packets. Then the packets are autoblocked to delineate the packets while providing a single Inter Block Gap per autoblock length and written on the tape. On read, the data is retrieved from the tape and deblocked to separate the packets. Each packet is separated into compacted sets of data. The compacted sets are directed to a plurality of decoders in turn and decompacted.