“Cloud computing” is basically the latest incarnation of grid computing, utility computing, virtualization and clustering. It differs in that it provides the ability to connect to software and data living on the Internet (the cloud) instead of on a hard drive or local network.
This type of cloud computing delivers a single application through the browser to thousands of customers using a multitenant architecture. On the customer side, it means no up-front investment in servers or software licensing; on the provider side, with just one app to maintain, costs are low compared to conventional hosting
2. Utility computing
Amazon.com, Sun, IBM, and others offer storage and virtual servers that IT can access on demand. Early enterprise adopters mainly use utility computing for supplemental, non-mission-critical
3. Web services in the cloud
Closely related to SaaS, Web service providers offer APIs that enable developers to exploit functionality over the Internet,rather than delivering full-blown applications.
4. Platform as a service
Another SaaS variation, this form of cloud computing delivers development environments as a service. You build your own applications that run on the provider’s infrastructure and are delivered to your users via the Internet from the provider’s servers.
5. MSP (managed service providers)
One of the oldest forms of cloud computing, a managed service is basically an application exposed to IT rather than to end-users, such as a virus scanning service for e-mail or an application monitoring service
6. Service commerce platforms
A hybrid of SaaS and MSP, this cloud computing service offers a service hub that users interact with.