CLOUD COMPUTING (Expected topic HCS MAIN EXAM )

Cloud computing is a general term for anything that involves delivering hosted services over the Internet. These services are broadly divided into three categories :

Infrastructure as a S ervice(IaaS)

Platform as a Service(PaaS)

Software as a Service(SaaS)

Cloud computing is a new technology where data is outposted and stored in a secure environment (the cloud) and then provided as a service online, either by subscription or on a pay on demand basis to costumer.

A simple example of cloud computing is yahoo email or gmail, etc. One does not need software or a server to use them. All a consumer needs is just an internet connection and you can start sending emails. The server and email management software is all on the cloud (internet) and is totally managed by the cloud service provider Yahoo, Google etc. The consumer gets to use the software alone and enjoy the benefits.

The term ‘cloud’ is used as a metaphor for the internet, based on the cloud drowing used in the past to represent the telephone network, and later to depict the internet in computer network diagram as an abstraction of the underlying infrastructure it represents. Typical cloud computing providers deliver common business applications online that are accessed from another web service or software like a web browser, while the software and data are stored on servers.

Cloud computing is internet based computing , whereby shared resources, software, and information are provided on computers and other devices on demand, like the electricity grid. Cloud computing describes a new supplement , consumption, and delivery model for IT services based on the internet, and it typically involves over the internet provision of dynamically scalable and often virtualised resources. Cloud computing allows consumers and businesses to use applications without installation and access their personal files at any computer with internet access. This technology allows for much more efficient computing by centralising storage ,memory,processing and bandwidth.

A cloud service has three distinct characterstics that differentiate it from traditional hosting. It is sold on demand , typically by the minute or the hour, it is elastic- a user can have as much or as little of a service as he or she wants at any given time and the service is fully managed by the provider. Significant innovations in visualisation and distributed computing, as well as improved access to high speed internet and a weak economy, have accelerated interest in cloud computing.