Accelerator Definition, What is Accelerator

Accelerator is usually a device or program designed to improve the speed of a hardware peripheral or software program.

A good example of an accelerator would be a graphics or 3D accelerator. A graphics accelerator is a hardware peripheral that contains its own processor and RAM enabling the card to perform at accelerated speeds without decreasing the performance of the computer.

Other examples of accelerators are various utilities used to increase the performance of hardware devices. For example, a download accelerator is used to help increase the speed of download times on computer modems.

Hardware Accelerator

In computing, hardware acceleration is the use of hardware to perform some function faster than is possible in software running on the normal (general purpose) CPU. Examples of hardware acceleration include blitting acceleration functionality in graphics processing units (GPUs) and instructions for complex operations in CPUs.

The hardware that performs the acceleration, when in a separate unit from the CPU, is referred to as a hardware accelerator, or often more specifically as graphics accelerator or floating-point accelerator, etc. Those terms, however, are outdated and have been replaced with more descriptive terms like video card or graphics card.

Web Accelerator

A web accelerator is a proxy server that reduces web site access times. Web accelerators may use several techniques to achieve this reduction:

• They may cache recently or frequently accessed documents so they may be sent to the client with less latency or at a faster transfer rate than the remote server could.
• They may freshen objects in the cache ensuring that frequently accessed content is readily available for display.
• They may prefetch documents that are likely to be accessed in the near future.
• They may compress documents to a smaller size, for example by reducing the quality of images or by sending only what's changed since the document was last requested.
• They may filter out ads and other undesirable objects so they are not sent to the client at all.
• They may maintain persistent TCP connections between the client and the proxy server.

Web accelerators may be installed on the client (browsing) computer / mobile device or on ISP hosted servers or both. Accelerating delivery through compression requires some type of host based server to collect, compress and then deliver content to a client computer.

As of July 2006, these applications generally serve to improve dial-up, broadband and other connections that users may not be getting the best speed from. Many users can achieve a 2 to 10 times speed increase in average browsing experience, while some report a 5 to 20 times speed increases for specific web sites and pages. Many ISPs offer web accelerators as a part of their dial up and broadband services. Web accelerators are typically designed for web browsing and, sometimes, for e-mailing and can not improve speeds of streaming, gaming, P2P downloads or many other Internet applications.

Other web accelerators are targeted at the web site or web application owners. This type of web accelerator is installed in front of web servers and application servers and use a variety of the above techniques to improve performance to all users accessing the accelerated web sites or web applications.