ABSTRACT
Traditional computing systems use a complex hierarchy of volatile and nonvolatile (NV) memory technologies (largely to manipulate data) and data-storage technologies (largely to store data) in order to achieve a reasonable balance of performance, cost, and endurance. žis leads to considerable complexity in operating systems and soªware applications, which adds cost and decreases reliability. Magnetic disk drives are the cheapest form of non-archival data storage with a cost about 10-100 times lower per bit than solid-state memory technologies. Disk
drives are capable of inexpensively storing huge amounts of data: typical capacities exceed several hundred gigabytes (GBs) today. However, hard disk drives (HDDs) have a limited mean time to failure. A hard drive includes a ¢xed read/write head and a moving media upon which data are written. Devices with moving parts always are intrinsically unreliable with the possibility of mechanical failure and complete loss of stored data.
