The IBM adaptive lossless data compression (ALDC) family of products uses a
derivative of Lempel-Ziv encoding to compress data. Several variables affe
ct the compression performance of the ALDC algorithm: data content, history
size, and data extent. As ALDC compression is integrated into different ap
plications, restrictions are placed upon these variables that affect the ov
erall compression performance of the system. More complex applications requ
ire further support for higher-order data structures such as variable-lengt
h segments, error recovery, and expansion. The IBM Blue Logic ALDC and embe
dded lossless data compression (ELDC) cores have been developed to work in
these application environments. These cores and the issues associated with
integrating data compression into a system are discussed.