Editing Network-attached storage (section)

==Overview==
A NAS device is optimised for [[file server|serving files]] either by its hardware, software, or configuration. It is often manufactured as a [[computer appliance]]{{snd}} a purpose-built specialized computer. NAS systems are networked appliances that contain one or more [[hard disk drive|storage drives]], often arranged into [[logical disk|logical]], redundant storage containers or [[RAID]]. Network-attached storage typically provide access to files using network file sharing protocols such as [[Network File System (protocol)|NFS]], [[Server Message Block|SMB]], or [[Apple Filing Protocol|AFP]]. From the mid-1990s, NAS devices began gaining popularity as a convenient method of sharing files among multiple computers, as well as to remove the responsibility of file serving from other servers on the network; by doing so, a NAS can provide faster data access, easier administration, and simpler configuration as opposed to using general-purpose server to serve files.<ref>{{Cite web|url=http://www.infostor.com/index/articles/display/55961/articles/infostor/volume-2/issue-4/news-analysis-trends/nas-advantages-a-vars-view.html|title=NAS advantages: A VARs view|website=www.infostor.com|date=April 1, 1998|access-date=26 February 2019|first=Ron|last=Levine}}</ref>

Accompanying a NAS are purpose-built [[hard disk drive]]s, which are functionally similar to non-NAS drives but may have different firmware, vibration tolerance, or power dissipation to make them more suitable for use in RAID arrays, a technology often used in NAS implementations.<ref>{{cite web|title=Marketing bulletin: NAS versus desktop - Evaluating HDDs for NAS applications|url=http://www.seagate.com/files/www-content/product-content/nas-fam/nas-hdd/en-us/docs/nas-vs-desktop-marketing-bulletin-mb633-1-1304us.pdf|website=seagate.com|access-date=29 December 2021}}</ref> For example, some NAS versions of drives support a command extension to allow extended error recovery to be disabled. In a non-RAID application, it may be important for a disk drive to go to great lengths to successfully read a problematic storage block, even if it takes several seconds. In an appropriately configured RAID array, a single bad block on a single drive can be recovered completely via the redundancy encoded across the RAID set. If a drive spends several seconds executing extensive retries it might cause the RAID controller to flag the drive as "down" whereas if it simply replied promptly that the block of data had a checksum error, the RAID controller would use the redundant data on the other drives to correct the error and continue without any problem.