What is a Server?


A Server is a (pretty much) normal computer that through a network receives requests and executes them. It is not defined by its hardware configuration but rather by the software (function) it runs and as such the requests it can service.

HARDWARE

Whilst there are generally some differences when comparing a PC to a Server, these differences are mainly in number of components and are there for 2 reasons;

  1. More speed and power. Whilst a normal home PC has to service the requests of one user, a server needs to service hundreds and even thousands of users at any given time. As such, whilst a home PC might have 4GB or RAM, a server will have 16 times that much. Servers will also generally have more than 1 CPU and multiple Power Supply Units.
  2. Redundancy. Servers can experience the same issues as a normal home PC! Since so many people depend on a server, more of the same hardware is built into a server so if something fails an online backup takes over and no downtime is experienced (Online backup means something that’s already installed and working in standby mode). In fact, no one would notice a server’s power supply just went bust as a secondary power supply unit will immediately take over.

To debunk myths and common misconceptions about servers, any normal PC or laptop could potentially act as a server. Whilst hardware requirements are generally higher than your typical home computer (due to the amount of requests it needs to service) there isn’t much difference between the hardware of a home computer and a server…

What a typical home computer setup might look like:

home computer

And a server…

server

Whilst they certainly look different, the differences we see here serve specific functions…

When it comes to home computing, one PC is enough to get the job done. Servers on the other hand need to service thousands and sometimes millions of users and as such they require working in larger numbers. To use space efficiently, they need to be stackable. This allows more servers to be placed in less space, generally in a rack:

rack

Hey, where are the monitor and keyboard?

Since servers are accessed through a network, there is no need for any input devices such as a mouse and a keyboard or a monitor… If a technician or an administrator needs to work on a server, it is accessed remotely. Should there be an issue with the server that’s making it inaccessible through the network, a normal monitor, keyboard and mouse can still be hooked up to the server.

What’s inside a Server?

If we had to look inside a server and a home computer to compare them, we can see a number of similarities:

server

As we can see, both home PCs and Servers have the same type of components, only in larger numbers.

Whilst the PC has 2 sticks of RAM, the server has 16! The PC in picture has 2 hard-drives and the server has 3 located at the front. A server might have more CPUs that a normal home PC to help it process requests faster.

Why are the hard disks located at the front? Well, hard-disk are the components most likely to fail (and they do!) due to having mechanical, moving parts. So they are located at the front foreasy, quick access should one need to be replaced.

SOFTWARE

As the defining aspect of a Server, robust and stable software runs atop powerful hardware to enable servers to perform a certain function.

The Operating System

Just like your normal home PC, servers need an operating system. Windows have their own Server-based Operating Systems the latest one being Windows Server 2008 R2 (R2 means Release 2). Windows Server Operating Systems look very much alike Windows XP or Windows 7, with a host of added features and functions! The still have a ‘Start’ button and can run Office pretty much the same way as Windows XP however it is built to service multiple users at the same time rather than just one.

Of course, Windows is not the only Server Operating System out there. Linux is widely used as are UNIX, VMware ESXi and Mac’s latest OS X Lion Server amongst others.

Services

Services running on a server characterize the Server’s function:

Web Server

IIS (Windows) and Apache are the 2 most common services that provide web services. Ever visited a website? A Web Server provides the webpage you see and handle requests you might send and receive during your session.

Email

To send and receive email, a service handling this type of information process and handles all requests. Microsoft’s Exchange is used the world over employed by business world-wide. IBM has its own solution bearing the name of Lotus Notes. Open Source programs exist in abundance and include Postfix, Cyrus IMAP and others…

Of course, Web and Email are just the tip of the iceberg when it comes to listing all the services that we interact with every day. DHCP and DNS, OSPF and HTTP are services and protocols we use everyday yet few of us tend to know about. The internet is very clever at masking the cogs and gears that turn this huge machine we have come to rely on so heavily.

We will continue to add more articles describing these essential services from time to time taking you on a journey through the underworld of IT. In the meantime, visit our website at www.uniblue.com to see how we are trying to make it a better place.

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