Sometimes the most expensive machine is not the one that provides the best performance. Your demands on the platform hardware are based on many aspects and affect many components. Let's discuss some of them.

This discussion relies on the specific definitions of various hardware and operating-system terms. Although you may be familiar with the terms below, we have explicitly provided definitions to make sure there is no ambiguity when we discuss the hardware strategies.

Cluster
A group of machines connected together to perform one big or many small computational tasks in a reasonable time. Clustering can also be used to provide failover, where if one machine fails, its processes are transferred to another without interruption of service. And you may be able to take one of the machines down for maintenance (or an upgrade) and keep your service running—the main server simply will not dispatch the requests to the machine that was taken down.

Load balancing
Say that users are given the name of one of your machines, but it cannot stand the heavy load. You can use a clustering approach to distribute the load over a number of machines (which gives you the advantages of clustering, too). The central server, which users access initially when they type the name of your service into their browsers, works as a dispatcher. It redirects requests to other machines, and sometimes the central server also collects the results and returns them to the users.

Network Interface Card (NIC)
A hardware component that allows your machine to connect to the network. It sends and receives packets. NICs come in different speeds, varying from 10 MBps to 10 GBps and faster. The most widely used NIC type is the one that implements the Ethernet networking protocol.

Random Access Memory (RAM)
The memory that you have in your computer (comes in units of 8 MB, 16 MB, 64 MB, 256 MB, etc.).

Redundant Array of Inexpensive Disks (RAID)
An array of physical disks, usually treated by the operating system as one single disk, and often forced to appear that way by the hardware. The reason for using RAID is often simply to achieve a high data-transfer rate, but it may also be to get adequate disk capacity or high reliability. Redundancy means that the system is capable of continued operation even if a disk fails. There are various types of RAID arrays and several different approaches to implementing them. Some systems provide protection against failure of more than one drive and some ("hot-swappable") systems allow a drive to be replaced without even stopping the OS.