Cloud Computing

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                 Situation 1: I am looking for a house. My first constraint, being a middle class man, obviously is money. The House owner here is ready to give his house on rent to me. But demands more than my budget. And this is a house which can accommodate more than 4 persons. Now we both came to a deal:

•          I shall share the house with 3 other persons.
•          They shall share the rent. 

Now the deal is both economical and efficient in the usage of the living space.

Situation 2: I want a cycle, I want it to be the latest, the best, but only for a month. Here came the cycle salesman. He gave me a fair deal, a decently modern cycle which I can own for myself just for 1 month after which I have to give him back his cycle with usage charge for his service.

                These transactions are pretty common in our daily life. Do you understand these? Then you have understood CLOUD COMPUTING except that, replace the house and the cycle with hardware and software.

                  Everything today is computerized. Even a small shop owner maintains the inventory in his personal computer. If this is the case, consider a huge enterprise which has umpteen branches and business process. But unlike a small shop owner, enterprise requires powerful computers. This investment is not one time and these systems require maintenance and continuous improvement over time. This lead to the idea of providing these infrastructures (both software and hardware) as services on a semi–permanent (rented) basis where you don’t add physical assets and are provided with great flexibility and choice in your purchase. This concept is known as Cloud computing.

Okay, Proper Definition:

Cloud computing is the way of providing computing resources, both hardware and software as service on a rented basis to users. The service providers take care of creating, updating, maintaining the necessary infrastructures removing the burden from users. Based on different computing resources, services include:

Infrastructure as a service (IaaS)

                Entire systems (virtual machines) will be provided to the users. Users can access the systems through internet. Users are responsible for the software needed. Service providers charge based on the resource allocated and consumed by the users.

Platform as a service (PaaS)

                In this model entire systems along with the operating systems and an environment to deploy application software are provided. Eg: Google App Engine

Software as a service (SaaS)

                While the above two models are used by companies, this one is more common and are used by us for our daily activities. Software are created by service provider and deployed over the internet for customers. End users use these services on a subscription basis. Eg: Email providers like Yahoo, Gmail etc.

Storage as a service (STaaS)

                As the name suggests storage is provided getting rid of maintaining separate storage devices by the end users. Eg: Windows Skydrive

Advantages:-

•      No responsibility of creation, maintenance of systems.
•       Easy implementation and economical.
•       Flexibility in hardware and software i.e., pay as you use.
•       Easy up-gradation to match current technology.
•       Efficient usage of resources.
•       Location independence i.e., accessible from anywhere.

Constraints:-

•          Data security.
•          Need for high speed internet connection (Essentially a big constraint for a country like ours).
•          Universal standardization required which makes interoperability among providers      difficult as of now.
•          Dependent on service providers even for trivial applications.