and replaces matched data by a reference to the pattern x rl is a slight improvement on x match that adds run length rl encoding of consecutive words that contain only zeros frequent pattern compression fpc uses only the information within a 32 bit word to determine the compression instead of a dictionary fpc assumes that certain patterns such as small integers and all zeros appear in memory data more frequently than others and looks at one 32 bit word at a time and applies one of seven compression schemes using a three bit code to the compressed data to indicate which scheme it applied the cache packer c pack algorithm uses a combination of static compression and dictionary lookup in c pack a 32 bit word is tested against some simple patterns including patterns that are already in the dictionary and a word can be compressed if a dictionary entry contains even a partial match the newer compression schemes include ssdpmc2 statically seeded directory partial match compression 2 which looks at 32 bit words and encodes them per a defined format and uses a dictionary with eight 32 bit entries to store potentially reused data words another compression scheme is the mpack compression algorithm which was designed for low latency decompression for compressed.