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Compression Buffer Initial Detection Algorithm

IP.com Disclosure Number: IPCOM000110389D
Original Publication Date: 1992-Nov-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 1 page(s) / 38K

Publishing Venue

IBM

Related People

Debry, R: AUTHOR [+6]

Abstract

Compression algorithms provide a non-data state mechanism which trade processing resources (compression/uncompression) for space resources. Compression therefore becomes highly inefficient for certain data states.

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This is the abbreviated version, containing approximately 83% of the total text.

Compression Buffer Initial Detection Algorithm

       Compression algorithms provide a non-data state mechanism
which trade processing resources (compression/uncompression) for
space resources.  Compression therefore becomes highly inefficient
for certain data states.

      This compression operation initializes from each data object
header.  If the object appears to be pre-compressed, then the object
is not operated on.  The data mover function thus optimizes for
minimal elapsed time and minimal data storage resource utilization.

      In the ESMS base function in a Unix* environment, a data move
method is defined which resolves each data object's (hereinafter
called 'file') state information.  The specific current state of the
file is determined based upon field information which a
pre-compression function analyzes.  If the file has been compressed
previously by another compression process, the file is bundled into a
'token group' in its current form and propagated to an Archive Server
(an MVS host in the current implementation).

      If the file is not compressed, then normal compression
commences.  Multiple compression normally degrades the compute
cycle/storage resource requirement; thus, the pre-compression
function avoids a sub-optimal data compression solution.  The
function tests the initial buffer state for a file by 'trial'
compression of a sample buffer and comparison of the length of the
buffer at pre-post compression times.  If the...