Network Attached Storage (NAS) consists of an externally powered box containing one or more hard drives. They are managed using an embedded operating system which is usually Linux but there are also some proprietary systems, such as Netgear (ZFS) and SNAP's Guardian OS, . NAS devices are normally connected directly to the network through a standard network cable and are configured using a web interface.
Data recovery from NAS devices requires an understanding of the file system structures. The operating system of choice for most NAS boxes is Linux as it offers a good network operating system and reliable file systems. Most of all, the Linux operating systems are very cheap compared to other server software, often free, bring the overall cost of the units right down and making them available to everyone that needs one.
RAID levels vary from between manufacturers, some use proprietary RAID based systems such as Infrant's X-RAID or those mentioned earlier.
NAS equipment is used mainly as a central network storage area where shares can be set up so that different users or departments can access the data they need. Many modern NAS boxes also contain built-in web servers and FTP servers and so can be used as stand-alone systems for web or file access separated from the main network helping security.
Warning: NAS is NOT an alternative for backup. Computer data should be backed up using a recognised backup policy.