I. Background of Cloud Computing(cont'd)
- Platform as a Service (PaaS)
PaaS delivers cloud-based application development tools in addition to services for testing, deploying, collaborating, hosting, and maintaining applications. It hides all the complexity of managing the underlying hardware, provides all the facilities required to support the complete lifecycle of building and deploying web applications and services entirely from the Internet. With PaaS, users can develop new applications or services in the cloud that do not depend on a specific platform to run, and can make them widely available to users through the Internet. The accessibility of PaaS offerings enables any programmer to create enterprise-scale systems that integrate with other web services and databases.
Two well-known PaaS solutions, Google AppEngine and Microsoft Azure, provide users with a development platform for creating distributed applications that can automatically scale on demand. Other PaaS service providers are 3Tera, RightScale, DataSynapse, Manjrasoft, Univa UD, Elastra and Enomaly.
- Software as a Service (SaaS)
SaaS is a model of software deployment where a provider delivers its software as a service to be used by customers on demand. Under the traditional SaaS model, an application resides at an offsite data centre where the service provider maintains data, servers and related hardware. End-users access the application remotely via an Internet browser. The SaaS model is predicated on a "one-to-many" or multi-client delivery model whereby an application is shared across clients, providing opportunities to customise the system to the needs of each customer.
Examples of SaaS are Salesforce.com and Clarizen.com, which respectively provide online Customer Relationship Management (CRM) and project management services. Google Apps provides desktop applications which are hosted in the cloud and replaces traditional desktop based Microsoft Office software. Northgatearinso offers on demand Human Resources (HR) solutions based on SAP Human Capital Management (HCM) module.
Worldwide revenue from public IT cloud services exceeded $16 billion in 2009 and is forecast to reach $55.5 billion in 2014, representing a compound annual growth rate (CAGR) of 27.4%. This rapid growth rate is over five times the projected rate of growth for traditional IT products (5%).
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