CA Compress/2 › Features

Features

The CA Compress/2 system provides a unique combination of capabilities:

High Degree of Data Compression

Data sets compressed by CA Compress/2 require as little as 10 percent, and commonly 35 percent, of their original space allocation.

Efficient Implementation

Application programs using the CA Compress/2 system to process compressed data sets may in some cases complete in less time than was once required to process uncompressed data sets.

Demonstrated Reliability

CA Compress/2 uses a check byte technique to ensure that no data is altered during compression and expansion.

Ease of Use

CA Compress/2 provides excellent compression without requiring you to provide information about the structure and content of records to be compressed. If you want to achieve compression ratios approaching the theoretical maximum, CA Compress/2's Record Definition Language (RDL) provides the opportunity to describe the record structure and content of the data set to be compressed. In the absence of user-coded RDL specifications, CA Compress/2 assumes standard defaults based upon attributes of the input data set to achieve excellent compression.

Flexibility

The RDL provides a powerful tool for constructing a compressed data set tailored to your specific requirements. User-specified fields can be exempted from compression, allowing sorting of compressed data sets without requiring prior re-expansion. Application programs can expand records selectively by examining fields exempted from compression, avoiding needless expansion overhead.

If the fields being sorted on are exempt from compression, sort utility programs can sort the records without expansion and recompression.

Similarly, if match key fields are exempted from compression, application programs containing logic to match records based on match key fields can perform the matching logic on the compressed records, limiting record expansion to only those cases which require further processing.

The RDL enables you to exempt fields from compression as well as to optimize compression. Fields in the record are defined by field type code specifications, which indicate the method of compression for the defined field. The available type codes let you define virtually any combination of field formats. Using the RDL is optional. If you omit RDL specifications, CA Compress/2 assumes default RDL specifications based upon data set attributes provided by JCL or by the data set label.