Content Addressed Storage (CAS) is another approach to storage hierarchies, along with Storage Area Networks (SAN) and Network Attached Storage (NAS), due to Information Lifecycle Management
(ILM). CAS storage is based on the IP protocol but works with objects, Binary Large Objects (BLOB), with fixed content rather than data blocks or files. Objects stored in CAS systems are identified by a unique name that also identifies their location in memory. A central index directory is not required. Due to the large BLOB objects, redundancies can be avoided and the authenticity of
the BLOBs can be guaranteed.CAS systems generally use hard disks and not magnetic tapes as storage media. The special requirements for CAS storage are the longevity of the data and its integrity
. Typical applications for CAS storage arein content management
. A significant advantage of CAS storage is the low storage requirement for backups and data archives compared to other storage systems.