Also called network server, a server is a computer designed to deliver information, process and manage multiple computer requests, and offer support services to other computers on the network. In other words, a server is a heavy-duty computer (typically) that primarily takes care of back-end tasks and can store and run loads of data at any given time. For example, when one accesses email using personal login credentials, the mail “server” processes and approves the request.
A server could serve computers on a local area network (LAN) or wide area network (WAN). LAN network comprises closely located inter-connected computers, such as in a room or building. These may serve few users. WAN connects computers located in different regions through the Internet and therefore can support several thousand users.
How Powerful Should a Server Be?
A server need not always be a robust computer. Even personal computers can run software that can be accessed by other computers on the network. But these are not typical servers as they are not supposed to be powered on 24 hours a day. Most servers are responsible for critical functions and need power supply round-the-clock. These servers are usually high-end computers with the latest and greatest hardware and software builds. When people talk about servers in general, they are actually talking about such servers that never fail (almost).
Server Types and Purposes
Servers serve multiple purposes and there are some dedicated to a certain task. For example, email services, online ticketing, social networking, etc. are a few dedicated tasks handled by servers. Based on purpose, a server could be categorized as:
A web server serves websites and their pages. Whenever a website address is typed into a web browser, the browser connects with the web server of that particular site and puts in the request for the page. The server processes the request and delivers the requested page.
A proxy server intermediates between a computer and server. When a client computer seeks certain resources such as web pages, online videos, e-books, games, etc., the proxy server looks up its local disk cache to see if the requested resources are cached. If not, the proxy server would seek resources from the actual server. This freshly sought resources would now get cached so that they could be delivered faster when the same request comes around next time.
A print server is a network computer that processes print-related jobs received from different computers on the same network. The server comes in handy as there is no need to depend on a single computer to perform print jobs.
An email server, as the name indicates, offers hosting infrastructure for sending and receiving emails over a network such as the Internet. Email services such as Gmail, Yahoo, Outlook, etc. use mail servers.
A database server offers different computers access to a database locally or over a network such as the Internet. A database is nothing but organized assortment of data.
Some of the other server types are blade server, file server, virtual server, standalone server, policy server and identity server.
Server Operating System
The operating system (OS) for a server is not necessarily the same as desktop operating systems. Server operating systems are usually more robust, secure and stable. The kind of OS required could vary with purpose. If the server is required to share files with a handful of users, a regular desktop OS should suffice.
Server operating systems would most likely not have the user interface people have become accustomed to on desktop operating systems. For instance, the installation process of a particular software program on a desktop OS may be different on server OS. The user tools may not be available. Since server operating systems are not meant to be used by regular users and security and stability are paramount, manufacturers skip unnecessary features and add in only the most essential traits.
Also, software for a server OS is invariably more expensive than regular software programs. In fact, a particular software application would cost higher on server OS than when purchased for a desktop computer. Some server operating systems such as Windows Server 2016 come built-in with all necessary software, usually not needing software programs to be separately installed. But certain other systems such as Linux are barebones and different functionalities may have to be added to them later.
Server hardware basically refers to the processor, power supply, hard drive, RAM, etc. Like server software, there are specialized server hardware made too. But these are not mandatory and regular hardware components can also be used.
Unlike traditional computer power supply, server power supply setup is roomier and can accommodate multiple power supplies. So if one of the power supply fails, another device can provide the electric energy required to keep the server running. If the impaired power supply is dead or cannot be retrieved, it could be swapped with a fresh device without having to reboot the server. Similar is the case with replacing bad server hard drives.