23-05-2014, 02:20 PM
Introduction to Cloud Computing
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INTRODUCTION
Cloud computing is everywhere and now a days it is receiving a great deal of attention, both in publications and among users. In this first section, we’ll discuss about what cloud computing is, its properties and various service and delivery models. Cloud computing is a jargon term without a commonly accepted non-ambiguous scientific or technical definition. In science, cloud computing is a synonym for distributed computing over a network and means the ability to run a program on many connected computers at the same time. The popularity of the term can be attributed to its use in marketing to sell hosted services in the sense of application service provisioning that run client server software on a remote location. Simply we can say Cloud Computing is a type of Internet –based computing that relies on sharing computing resources rather than having local servers or personal devices to handle applications.
Cloud Computing can be defined as a model for delivering information technology services in which resources are retrieved from the internet through web-based tools and applications, rather than a direct connection to a server. It enables ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. Cloud computing is so named because the information being accessed is found in the "clouds", and does not require a user to be in a specific place to gain access to it. This colloquial expression is used to describe a variety of different computing concepts that involve a large number of computers that are connected through a real-time communication network (typically the Internet).
Cloud Service/Delivery Models
Cloud computing providers offer their services according to several fundamental models: infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS) where IaaS is the most basic and each higher model abstracts from the details of the lower models. Other key components in XaaS are described in a comprehensive taxonomy model published in 2009, such as Strategy-as-a-Service, Collaboration-as-a-Service, Business Process-as-a-Service, Database-as-a-Service, etc. In 2012, network as a service (NaaS) and communication as a service (CaaS) were officially included by ITU (International Telecommunication Union) as part of the basic cloud computing models, recognized service categories of a telecommunication-centric cloud ecosystem.