What is server ?

In the first two hours,you heard the term “server ”used to describe a computer that shares its resources with other computers over a network. In the following sections, you learn more about servers what they are, how they are different from regular computers, and what they ’re used for.

What Is a Server?

A server is a powerful computer that shares its resources with other computers on a network. In brief terms, that ’s what a server is and what it does.But a server is a great deal more and, surprisingly,often a great deal less than your desktop computer. Server hardware is usually built around two primary needs:moving data quickly and ensuring the safety and integrity of data.

For starters, a server is usually a great deal more powerful than your desktop computer. Even if your desktop computer has a ten-zillion-Hertz Perfectium processor, chances are that it lacks the I/O, or throughput (generally, a loose measure of the speed at which a particular piece of hardware can move data), to adequately service other computers ’needs. No matter how fast your desktop computer is,if it can ’t move data off disks and onto a network wire quickly enough, it is not much use as a server. It ’s like a car ’s doughnut spare tire a desktop computer can function as a server computer in a pinch, but you don ’t want to make a regular practice of using it as your mission-critical system.

In basic terms,a server has as powerful a processor sometimes even more than one and as much memory as you can afford to put into it.Typically, a server is more powerful than your desktop systems.Although important, processor speed and memory are not the best measure of a server ’s usefulness, as you are about to discover.

A server usually provides some form of insurance against disaster most desktop computers don ’t.To return to the motor vehicle metaphor,servers have systems to deal with disasters for the same reason that 18-wheeler highway trucks have dual tires.If one of the dual tires blows,the other one can keep supporting the load,and the truck doesn ’t crash. In server terms,the “backup tire ”is called redundancy or fault tolerance and is a cornerstone of server architecture.Ultimately, fault tolerance simply means that your system isless likely to completely crash as a result of hardware failure. In the subsequent pages, you ’ll learn about I/O and fault tolerance as they apply to servers. We ’ll cover redundancy in more detail later in this hour.