06-08-2011, 02:57 PM
A computer cluster is a group of loosely coupled computers that work together closely so that in many respects it can be viewed as though it were a single computer. Clusters are commonly connected through fast local area networks. Clusters are usually deployed to improve speed and/or reliability over that provided by a single computer, while typically being much more cost-effective than single computers of comparable speed or reliability. Cluster computing has emerged as a result of convergence of several trends including the availability of inexpensive high performance microprocessors and high speed networks, the development of standard software tools for high performance distributed computing. Clusters have evolved to support applications ranging from ecommerce, to high performance database applications. Clustering has been available since the 1980s when it was used in DEC's VMS systems. IBM's sysplex is a cluster approach for a mainframe system. Microsoft, Sun Microsystems, and other leading hardware and software companies offer clustering packages that are said to offer scalability as well as availability. Cluster computing can also be used as a relatively low-cost form of parallel processing for scientific and other applications that lend themselves to parallel operations.
