IBM CDI5UG1107 Computer Accessories User Manual


 
82 IBM Sterling Connect:Direct for i5/OS User’s Guide
COMPRESS (*YES|*NO|X\xx\|C\cc|EXT)
specifies data compression, which reduces the amount of data transmitted as the file is copied from
one node to another. The file is automatically decompressed at its destination.
If compression is specified, Sterling Connect:Direct reduces the amount of data transmitted based on
the following rules:
Repetitive occurrences (ranging from 2–63) of the primary compression character are
compressed to one byte.
Repetitive occurrences (ranging from 3–63) of any other character are compressed to two bytes.
Specifying the primary compression character is recommended for text data or single-character
repetitive data. Extended compression generally offers improved compression for all types of data.
*NO
specifies no compression.
*YES enables compression. If *YES is specified, the default primary compression character is
PRIMEchar=X\40\ (hex 40=“ ”).
X\xx\ enables compression, where xx is the hexadecimal representation of the value to be used for the
primary compression character.
C\cc\ enables compression, where cc is the character representation of the value to be used for the
primary compression character.
EXT specifies that extended compression is used to search for repetitive strings of characters in data
and compress them to codes that are transmitted and converted back to the original string during
decompression. It is advantageous to specify this parameter when line transmission speeds are limited,
CPU is available, and data is repetitive.
CRC(*INITPARMS
|*NETMAP|*OFF|*ON)
Determines whether node and Process statement overrides for Cyclic Redundancy Check (CRC) are
allowed. If this value is set to *OFF, setting overrides for CRC checking will be ignored. The default
value is *INITPARMS.
*INITPARMS
specifies that the CRC setting is determined by the value for the initialization
parameter, TCP.CRC.
*NETMAP specifies that the CRC setting is determined by the value for the NETMAP parameter,
Cyclic Redundancy Check. The value for the initialization parameter TCP.CRC must be set to *ON
and the value for the initialization parameter TCP.CRC.OVERRIDE must be set to *YES.
*OFF specifies that CRC is disabled.
*ON specifies that CRC is enabled.
ECTUNING (ecclevel,ecwinsize,ecmlevel)
ECCLEVEL specifies the extended compression level, which affects how much CPU the extended
compression routines use. Higher compression levels use more CPU but achieve greater compression.
The valid values for this subparameter are 1–9, inclusive. The default value is *INITPARMS.
ECWINSIZE specifies the extended compression window size, which is specifically for the history
buffer that is filled from the user’s input buffer ( both compressing and decompressing). The window
specifies the amount of storage designated to maintain data previously read.
Note: Compression is CPU-intensive. Its effectiveness is dependent on data and line speed and
should be used only if it benefits the installation.