The NAS market divides mostly into two kinds storage systems:
SAN (storage area network) – serving virtual disks over the network. The common networks are Fibre-Channel (FC) and Ethernet (iSCSI and FCOE). The file systems (or lack of) is the responsibility of the computer affiliated with the virtual disk.
NAS (network-attached storage) – mainly serving files over Ethernet. The most common protocols are CIFS/SMB for Microsoft Windows clients and NFS for Linux/UNIX or DSP-based systems. NAS systems are used primarily for shared storage, as the same storage volume may be accessed concurrently from several systems.