*someone explains to me what are servers and nas*

[AdnanThePoorPanda]

plz

[orbit._]

A NAS (network attached storage) is basically a file server that you access via your network (e.g an SMB Share.) A server is a computer that likely runs 24/7, running something. This could be a game server to a hypervisor or even mathematical calculations. 

[AdnanThePoorPanda]

how they access the storage of those big business servers?

[Mira Yurizaki]

A server is typically a computer that accepts connections from other computers (called clients) from a network (internet or local) and provides a service to them.

 

A NAS is a type of server that primarily deals with managing storage devices over a netowrk

[AbsoluteFool]

A server is any computer that's job it is to serve content. Either be it internally or externally. A NAS can be a server. But most in the IT and hobbyist sections will not call it a server.

But that's the main perspective of "server" it's job it to serve people with something. Be it a web page, game, DHCP routing, The LTT forums, facebook, google search etc.

[Samueldes]

They are right. A server is a concept. Not a standard, nor a machine type. In my opinion, at a minimum, a server is designed for 24/7 operation without interruption. It may have Error-Correcting Code Memory (RAM). It may be powered through a UPS (Uninterruptible Power Supply). Or a generator. It can serve the needs of a whole country or a two-people business. It can have such redundancy, or none at all. Or very cool features such as remote access and remote Firmware configuration (iLO, IPMI, DRAC). It may be connected through fiber optic to a 100TB storage datacenter in another country. It may be searching for alien life or working against the clock to find an antidote for the SARS virus. It may run Irix 6.3 or Windows Server 2012. It is just there, listening to the queries. It serves a purpose.

[Samueldes]

NAS is simpler. NAS is redundant storage. Network-Attached Storage. Many computers can access it. It is used locally, it is usually not shared over the internet. It is designed for you or your (small) organization. It would probably be bad at handling numerous queries per second online, for example. You would need an Entreprise-grade SAN (Storage Area Network) for that. A NAS can be as simple as 2 hard drives replicated (RAID1, mirror), with a shared folder on your network. It could also be much more intricate, like iscsi netbooting other servers or diskless workstations for less client-side maintenance.