What is NAS?

NAS is a hard drive storage system - including configuration of RAID, with its LAN IP address than being connected to the computer department that is giving applications to workstation of network users. It has its own program for mapping and configuring file locations to network attached equipments. A Network-attached storage could be included as part of a more complete solution similar to SAN.
Description
NAS varies from traditional file serving and DAS or Direct Attached Storage in that the OS and other program on the NAS offer only the storage data's functionality, data access and the supervision of these functionalities. Moreover, the NAS unit doesn't limit clients to just one FTP. NAS systems typically contain 1 or more hard drives, often set into logical, superfluous of redundant arrays of independant disks (RAIDs) or storage containers, as traditional file servers do. NAS eradicates the responsibility of serving file from other servers on other network and could be deployed by way of commercial embedded units or through computers running NAS program.
NAS utilizes file-based protocols like NFS or Server Message Block (SMB). Contrast NAS's file based method and use of well understood protocols that has SAN (storage area network) that utilizes a block based approach and runs over SCSI over iSCSI or Fiber Channel.
Minimal functionality or stripped down OS are utilized on NAS PCs or devices that run protocols or file applications which offer the NAS functionality. A "leaned out" Free BSD is utilized in Free NAS, for instance, which is open-source NAS software intended to be organized on computer hardware. Commercial embedded equipments and consumer network appliances can utilize closed source OS and protocol implementations.
As these tools have IP addresses, they could be accessed directly.
In a Network-attached storage, since the storage are separately located to the server, program files are served more rapidly as they are not competing for no different resources.
Another benefit of Network Attached Storage is that, you can have different servers with dissimilar OS storage, management and backup of the data can be centralized even when you're in the environment
Some of the great advantages of this storage device include its expandability. It is so easy to add more storage. This as well brings an extra fault tolerance level to the network because you could include mirror RAID features.

If you are interested in learning more about Network Attached Storage, check this NAS web site.