Saturday, 18 May 2013


                                                       CLOUD COMPUTING

What is cloud computing?

Cloud computing is computing based on the internet which delivers IT as a service with pay-as-you-go pricing. The name “cloud” represents “Internet having indefinite shape and size with complex structure”.  Cloud computing technology allows for much more efficient computing by centralizing data storage, easy data processing and higher data bandwidth. A simple example of cloud computing is Gmail, we do not require to install it, we just need a web browser to run it.

Cloud computing has the power to access with any of the devices mobile, laptop, tablet desktop etc. we need just an internet connection.
The idea behind cloud computing technology is similar to the electricity that we all use at home, we don’t know how it is generated, where it comes from, we just pay the bill for what we use. Same is the case with cloud computing, we can use storage, connectivity and computing power, all the services are available on demand as you require and are delivered economically without compromising for security or functionality. Various cloud service providers are Rackspace, SkyDrive, and Amazon etc.

 Why cloud computing?

  • Complete virtual infrastructure: No Software = no onsite installation.     Cloud computing slashes the capital costs of getting up and running.
  • Reduced cost: Cloud computing can reduce both capital expense and operating expense costs, because the resources are used when needed and are paid as per use.
  • Highly scalability: Cloud computing allows for immediate scaling up or down, at any time when we require.
  • Improved accessibility: we can have access anytime, anywhere, making our life much easier provided we have an Internet connection.
  • Security: cloud computing technology is highly Secure than other traditional systems applications.
  • Easy Maintenance: cloud computing applications are very easy to maintain as they are not needed to be installed on computer and there is auto up gradation.
  • Highly customizable: Cloud computing allows deep customization one can customize the applications very easily on world-class cloud platform such as Salesforce .com etc.


There are basically four types of clouds that can be subscribed according to the need of an organization or individual.

1.Public Cloud - A public cloud can be accessed by any subscriber and it is shared across multiple organizations, it is managed by an external service provider.
2.Private Cloud - A private cloud is established for a specific group or organization and limits access only to that group or organization, in short we can say it is for private use.
3.Community Cloud - A community cloud is shared among two or more organizations that have similar cloud requirements.
4.Hybrid Cloud - A hybrid cloud is basically a combination of at least two clouds; the clouds may be the mixture of public, private, or community.

Cloud service models:

The cloud computing services are segmented into three categories based on service types namely Software as a Service, Platform as a Service and Infrastructure as a Service.

Fig: Layers of cloud computing along with examples.
Software as a Service (SaaS): In SaaS service model, applications are hosted by a vendor or service provider and made available to customers over a network, typically through Internet. A subscriber has access to both resources and applications, but has a least control over the cloud; there is no need to have a physical copy of software installed on devices. E.g.: Salesforce .com, net suit.

Platform as a Service (PaaS): PaaS is the platform that hosts applications provided in (SaaS). PaaS provider gives subscribers access to the components that a developer requires to develop and operate applications over the internet. Subscriber has more control over the cloud as compared with SaaS 
layer but lesser than (IaaS). E.g.: Google App Engine, and Heroku.

Infrastructure as a Service (IaaS): (Iaas) deals primarily with computational infrastructure. In cloud infrastructure service model the subscriber completely outsources the storage and resource components, such as hardware, software, servers and networking components that are required by him. Infrastructure as a service (IaaS)enables businesses to move information from on-site servers into the Cloud. In this service layer the subscriber has most of the control on cloud as compared with the other two layers.
E.g.: Google Compute Engine, Google Cloud Storage and Google Big Query are major examples of cloud infrastructure provider.