What is Distributed Computing

Distributed computing refers to the means by which a single computer program runs in more than one computer at the same time. In particular, the different elements and objects of a program are being run or processed using different computer processors.

Distributed computing is similar to parallel computing and grid computing. Parallel computing, though, refers to running a single program using a minimum of two processors that belong to one computer. Grid computing, on the other hand, refers to a more dedicated distributed computing setup - one whose computer 'members' are especially dedicated to the program being processed.

Distinct Characteristics

In a distributed computing setup, the program runs like it would in a single computer even when it is, in fact, using different computer processors. This means that no single computer carries the entire burden on system resources that running a computer program usually implies.

However, distributed computing is not actually used to lighten the load of an individual computer's processor. It is in fact done to be able to process or run complex and resource-draining programs with greater speed and efficiency. Distributed computing, in effect, can be deemed as an attempt to produce a virtual supercomputer out of hundreds or thousands of individual computers.

Dedicated Servers

The distributed computing setup is usually called a peer-to-peer architecture. In actual fact, however, distributed computing is not peer-to-peer since individual computers do not actually directly communicate with each other. There's at least one dedicated distributed computing management server that coordinates the efforts across the whole network of computers that are contributing their system resources to the collective effort.

In a distributed computing setup, there is one or more servers which contain the blueprint for the coordinated program efforts, the information needed to access member computers, and the applications that will automate distribution of the program processes when such is needed. It is also in the distributed computing administrative servers that the distributed processes are coordinated and combined, and they are where the program outputs are generated.

How Distributive Computing Works

A computer that is part of a distributed computing network usually has a program installed in it that is its direct link to the administrative server or servers. The software remains dormant in the individual computer until such time that the computer's system becomes idle (the user is not using his resources). At this point, the software will be activated and will inform the administrative server about available resources in the computer. The administrative server will respond by sending an application package to the requesting computer. The moment the user has need of his own resources again, the management server will immediately relinquish the resources that it has been monopolizing, back to the owner of the computer.

source: techfaq