 Novell GroupWise was built on single-instance storage which accounts for its large capacity.ISO CD/DVD image files can be optimized to use SIS to reduce the size of a CD/DVD compilation (if there are enough duplicated files) to make it fit into smaller media.SIS is related to system wide file duplication search and multiple file instance detection tools such as the P2P application BearShare (5.n Versions and below) but differs in that SIS reduces storage utilization automatically and creates and retains symbolic linkages, whereas Bearshare allows for manual deletion of duplicates and associated user level file system, Windows Explorer type of icon links.