MODIFY COMPRESS command


Change the compression levels set by the APPL definition statement:

>>-MODIFY-- --procname--,--COMPRESS--,--ID--=--appl_name-------->

>--+-,--CMPAPPLI--=--input_limit-------------------------------+-><
   +-,--CMPAPPLO--=--output_limit------------------------------+   
   '-,--CMPAPPLI--=--input_limit--,--CMPAPPLO--=--output_limit-'


Change the compression level set by start option:

>>-MODIFY-- --procname--,--COMPRESS----------------------------->

>--,--CMPVTAM--=--overall_limit--------------------------------><

Abbreviations

Operand	Abbreviation
MODIFY	F

Purpose

Using the MODIFY COMPRESS command, you can change the value of the data compression levels originally set by the CMPVTAM start option or by an APPL definition statement.

The levels of compression available are in the range 0–4:

0: No compression
1: Run-length encoding (RLE)
2: Small adaptive compression table
3: Medium adaptive compression table
4: Large adaptive compression table

See the z/OS Communications Server: SNA Network Implementation Guide for additional information about compression.

Note: You can use the MODIFY VTAMOPTS command (CMPVTAM operand) to change the compression level set by the start option.

Operands

procname

The procedure name for the command. If procname in the START command was specified as startname.ident, where startname is the VTAM® start procedure and ident is the optional identifier, either startname.ident or ident can be specified for procname.

If procname in the START command was startname, startname must be specified for procname.

CMPAPPLI=input_limit

Specifies the input compression limit for the application. This operand allows compression-level limits for a specific application to be set lower than the overall limit specified by the CMPVTAM start option.

The valid range is 0–4. Zero specifies no compression.

The valid range is 0–1. Zero specifies no compression.

The limit specified by this operand is in effect only during sessions for which the application acts as the PLU and when the limit is lower than that specified by the CMPVTAM start option.

CMPAPPLO=output_limit

Specifies the output compression limit for the application. This operand allows compression-level limits for a specific application to be set lower than the overall limit specified by the CMPVTAM start option.

The valid range is 0–4. Zero specifies no compression.

The valid range is 0–1. Zero specifies no compression.

The limit specified by this operand is in effect only during sessions for which the application acts as the PLU and when the limit is lower than that specified by the CMPVTAM start option.

CMPVTAM=overall_limit

Specifies the overall compression limit for VTAM sessions. The new compression limit takes effect on new sessions that are started after you issue this command. Sessions that were started before this command are not changed.

The valid range is 0–4. Zero specifies no compression.

The valid range is 0–1. Zero specifies no compression.

ID=appl_name

Specifies the name of the application to which compression applies. This allows modification of the compression limit for the session as set in the APPL definition statement. The ID operand is required when either CMPAPPLI or CMPAPPLO is specified.