• NAS devices contain an optimized OS that implements a host-independent file system
NAS appliance
Network-attached storage (NAS): NAS devices provide access to storage over the LAN. It uses a File I/O architecture. A NAS device is essentially a specialized file server that is optimized for serving storage (sometimes called a “thin server”). Some NAS devices use customized versions of standard operating systems, such as Windows, UNIX, and Linux. The NAS device, instead of the host, manages the file system; storage sits “in front” of the server.
NAS devices typically implement a host-independent file system. The NAS server translates between its own file system and the file system used by the clients that access its storage resources, allowing multiple operating systems to access the same storage resources. Storage capacities associated with NAS have continued to increase as new server heads deal with very large storage subsystems. NAS can also function as a Gateway to storage on the SAN.