Overview and planning of zEnterprise Data Compression (zEDC)

In todayss z/OS® environment, many installations want to compress certain types of data to occupy less space while it is not in use, and then restore the data when necessary. Using zEnterprise® Data Compression (zEDC) to compress data might help to reduce CPU cost and elapsed time of data compression compared to traditional software-based compression services, such as CSRCESRV and CSRCMPSC. zEDC can also decrease the cost of applications that use host-based compression that are running on z/OS.

zEDC supports the DEFLATE compression data format, which compresses data by using the following algorithms, which are defined by RFC 1951:
  • LZ77
    • Replaces repeated string with length, back pointer pairs.
    • Points back up to 32 K.
  • Huffman coding
    • Variable length encoding of characters.
    • Minimize bit length of a stream of characters by assigning shorter codes to more frequent characters.
    • Data and length, back pointer pairs are Huffman encoded.
For more details, check the IETF standard RFC 1951.
Figure 1. Compression and Decompression Workflow
An image that shows the workflow for what happens when data is compressed and when it is decompressed.

For help with getting started, and access to various technical resources about Integrated Accelerator for zEDC, see Integrated Accelerator for zEDC.