A mass storage device that is connected to a network and extends the memory capacity is called NAS. In order to avoid installing and administrating a dedicated file server a NAS can be used. A NAS usually is
easy to install
easy to administrate because its function can be specifically adjusted to its purpose
Lots of causes of error are being avoided from the start, because there are no unnecessary and overly complex configurations that have to be made. File based services such as NFS or SMB/CIFS are the core functions. That is why, NAS systems are often also called Filers. A NAS can either have its own hard disk space (NAS Appliance) or be connected to a Storage Area Network (SAN).