Overview of Cloud Computing

Need for Cloud Computing – Changing business models and buying behavior

Defining Cloud Computing: What is Cloud Computing
Commoditization of IT services delivery along with changing buyer behavior is accelerating a shift in IT delivery model. Firms are looking to get all IT solutions as a service. Organizations are preferring outside service providers assembling, managing and monitoring the services for them inspite of going with the traditional self integrating service delivery model.

Cloud Computing Evolution 
Cloud Computing has linage with ASP, Grid Computing, Utility Computing, Adaptive Computing, Hosting, SOA and SaaS. The output of Cloud Computing Service Model is Service and only Service without concerning about – how IT is delivered to the business – from where, how, which all services, by whom and why.

Cloud Computing Services types: Cloud Computing services classification
Cloud services could be delivered as Application-as-a-service, Database-as-a-service, Desktop-as-a-service, Storage-as-a-service, Disaster recovery-as-a-service, Integration-as-a-service, Testing-as-a-service, Management-as-a-service, Middleware-as-a-service, Hardware-as-a-service, Platform-as-a-service, Infrastructure-as-a-service, Software-as-a-service etc.

Cloud Computing services are broadly classified into three categories: IaaS (Infrastructure-as-a-service), PaaS (Platform-as-a-service) and SaaS (Software-as-a-service) .

  1. Software as a Service (SaaS): i.e. Applications as a service (interactive or front end part) – examples of SaaS: Yahoo mail, Google docs, Salesforce.com, SAP on SaaS, Oracle on SaaS, NetSuite , on-demand CRM and ERP applications.
  2. Platform as a Service (PaaS): i.e. Platform / middle ware as a service (interfacing or front office end)– examples of PaaS: Salesforce.com's Force.com, Google's App Engine, and Microsoft's Azure.
  3. Infrastructure as a Service (IaaS): i.e. Infrastructure as a service (storage or back office end) examples of IaaS: Amazon Web Services (AWS), Amazon Elastic Compute Cloud (EC2), Flexiscale.