Expanz! is a drive compression system consisting of an expansion co-processor card and a set of software. It competed against Stacker, DoubleDisk and SuperStor. However Expandz! never made a software-only system. It worked a little differently as it compressed an entire partition rather than using an uncompressed host partition. While a hardware co-processor was useful for slower computer, software based solutions were able to surpass its performance with newer, faster CPUs.