Compression Options Available - ZLIB1 through ZLIB9

Document ID : KB000027858
Last Modified Date : 14/02/2018
Show Technical Document Details

These compression options were developed for sites that need increased performance and require high compression with minimum overhead. Examples of the types of files that benefit most from the use of compression are text or report files. Testing is highly recommended since compression may slow down file transfers that use a high speed connection.

They are available with

  • CA-XCOM Data Transport for z/OS & OS/390 Release 3.1 0406/SP03 and higher.
  • CA-XCOM Data Transport for z/OS & OS/390 Release 3.1 0310/SP02 with apars applied.
  • CA-XCOM Data Transport for UNIX & LINUX Release 3.1 0312/SP02 and higher.
  • CA-XCOM Data Transport for Windows Release 3.1 0312/SP02 and higher.

Both partners must support this compression in order to be able to use it.

CA-XCOM Data Transport has implemented levels 1 through 9.

Prior to this, the only ZLIB compression level available for use by XCOM was the default of "6". After the enhancement, the levels of ZLIB compression will be selectable and may be used when sending to other platforms that have the enhancement installed. If the partner does not support this compression, the compression will be negotiated down to COMPRESS=YES and an informational message will be displayed in the log.

The following statements show how to specify these varying levels of ZLIB compression:

COMPRESS=ZLIB1 (This invokes ZLIB Level 1 compression)
COMPRESS=ZLIB2 (This invokes ZLIB Level 2 compression)
COMPRESS=ZLIB3 (This invokes ZLIB Level 3 compression)
COMPRESS=ZLIB4 (This invokes ZLIB Level 4 compression)
COMPRESS=ZLIB5 (This invokes ZLIB Level 5 compression)
COMPRESS=ZLIB6 (This invokes ZLIB Level 6 compression)   NOTE: This was this previous ZLIB default
COMPRESS=ZLIB7 (This invokes ZLIB Level 7 compression)
COMPRESS=ZLIB8 (This invokes ZLIB Level 8 compression)
COMPRESS=ZLIB9 (This invokes ZLIB Level 9 compression)

Please note that as the level of ZLIB compression is increased, the CPU requirements also increase. It is up to the customer to decide which, if any, level of ZLIB is appropriate based on the intensity of compression required, the data content, and the availability of CPU resources.