COMPRTN keyword

The COMPRTN keyword specifies the name of the compression routine that IMS HP Image Copy invokes to compress output image copy data.

This keyword is effective when COMP=Y is specified.

Functions that support this keyword
  • Image Copy function
  • Create Image Copy function
Statements that support this keyword
  • GLOBAL statement
  • GROUP statement
  • IC/AIC statement
  • CIC/ACIC statement
  • CRC statement
Site default option
Supported
Related keywords
Format
Read syntax diagramSkip visual syntax diagramCOMPRTN=FABJCMP1FABJCMP2FABJCMP3FABJCMP4
FABJCMP1
FABJCMP2
FABJCMP3
FABJCMP4
The name of the compression routine. IMS HP Image Copy provides four compression exit routines: FABJCMP1, FABJCMP2, FABJCMP3, and FABJCMP4. Specify one of these compression routines to be called by the Image Copy function or the Create Image Copy function.

If the COMP=Y keyword is specified without the COMPRTN keyword, FABJCMP1 is used as the default.

The same compression routine is automatically called in Recovery function jobs to decompress the compressed data.

The following table summarizes the compression routines.
Table 1. Compression routines of IMS HP Image Copy
Compression routine Compression algorithm
FABJCMP1 Runs repeated character compression. Free space can also be compressed.
FABJCMP2 Runs only free space compression. Segmented data is not compressed.
FABJCMP3 Runs repeating-characters compression of the z/OS® program compression method. Free space might also be compressed.
FABJCMP4 Runs the repeating-characters compression of the z/OS program compression method. This routine runs the block compression, which does not distinguish between the data portion, free space, and unused space in the database.
Default value
FABJCMP1
Note: The default value for the COMPRTN keyword under IMS Database Reorganization Expert is FABJCMP3.
Usage notes
  • If you want to create a compressed image copy data set for a DEDB that has SDEP segments, you must use FABJCMP4. FABJCMP1, FABCMP2, and FABJCMP3 cannot be used for a DEDB that has SDEP segments.
  • If the IDRC feature is installed and is active on the native tape drive, software compression is suppressed for the IC1, IC2, or both output data sets except when FABJCMP2.
  • If you want to use the software compression for the tape device on which the IDRC feature is active, specify the COMPMODE keyword to deactivate IDRC.