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CA Compress has the following features:
CA Compress provides a wide choice of implementation methods. This flexibility enables you to select a compression algorithm and implementation mode best suited to the installation requirements. For example, you can meet the requirements for maximum convenience and minimum overhead by using the Super Express algorithm, and you can meet the requirements for maximum compressibility by custom tailoring a compression algorithm for a specific data set, and implementing compression immediately. A balance of overhead and compression can be achieved by selecting from a number of intermediate algorithms and implementation modes.
Distributed with CA Compress are several standard Huffman tables. The Huffman tables were designed to offer a high degree of compression for the most common types of data. So, you do not need to create and maintain your own compression tables.
Distributed with CA Compress are several standard dictionaries, built using different types of data.
CA Compress lets you develop compression implementations specifically designed for your data sets. This customization takes into consideration the unique file and record characteristics of a data set. In addition, the data that is currently in the data set is used to develop the most efficient compression tables for that file. The compression analysis facilities let you experiment with the development process and fine-tune the compression implementation.
CA Compress helps ensure the accuracy of your data by performing an integrity check on every record during compression and expansion processing. CA Compress includes integrity checking in its implementation of IBM Hardware Compression, giving Hardware Compression additional integrity.
CA Compress provides fully transparent support of VSAM KSDS and ESDS data sets, and physical sequential data sets using QSAM or BSAM. Physical sequential data sets are also supported in an application-transparent mode through CA Compress Subsystem Services.
VSAM Performance Enhancement (VPE) reduces I/O overhead while processing VSAM data files. But it is a component of CA Compress and can be used independently also. As data are read and written by the application program it is expanded and compressed as necessary.
The CA Compress Interactive User Interface (IUI) lets you interactively select data sets, execute test compression, evaluate compression statistics, and implement compression on the data sets. And, the IUI provides a wide selection of maintenance and utility functions in support of data compression.
The VSAM space release function lets you free the DASD space gained by file compression, for other uses.
Each test compression run generates a Compression Testing Report, which provides statistics for various compression algorithms and DASD utilization information. Analysis information is provided in a clear, concise format.
The exclusion processing feature lets you process compressed files without expanding the data. For example,
CA Compress-controlled data sets are typically excluded from compression and expansion during backup and recovery processing.
Safeguards prevent inadvertent access to compressed VSAM data sets when CA Compress is inactive, avoiding possible corruption.
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