**8. Grid and cloud computing**

This is the power of all time computing; creating a single universal source of computing power by making computational and data resources available to users and applications programmers on a scale never before possible. The Grid and Cloud Computing concentrates on high performance computing, Web services and grid services.

The *Dedicated server* is slowly starting to vanish and being replaced by *Cloud Computing*, however people are still afraid of security issues and letting go of their data on the cloud.

It is predicted that as they start getting on the cloud bandwagons, they would be using *Virtual Private Server* (VPS) which is fairly common among hosting solutions on the cloud where people share resources with the other clients on a particular server.

A set of characteristics that helps distinguish cluster, Grid and Cloud computing systems is listed in Table 1. The resources in clusters are located in a single administrative domain and managed by a single entity whereas, in Grid systems, resources are geographically distributed across multiple administrative domains with their own management policies and goals. Another key difference between cluster and Grid systems arises from the way application scheduling is performed. The schedulers in cluster systems focus on enhancing the overall system performance and utility as they are responsible for the whole system. However, the schedulers in Grid systems called resource brokers, focusing on enhancing the performance of a specific application in such a way that its end-users requirements are met. Cloud computing platforms possess characteristics of both clusters and Grids, with its own special attributes and capabilities such strong support for virtualization, dynamically composable services with Web Service interfaces, and strong support for creating 3rd party, value added services by building on Cloud compute, storage, and application services. Thus, Clouds are promising to provide services to users without reference to the infrastructure on which these are hosted (see table 1).
