Cloud computing is an internet based new age computer technology. It is the next stage technology that uses the clouds to provide the services whenever and wherever the user need it.It provides a method to access several servers world wide.

The main benefits of cloud computing are:

• Data backup and storage of data.
• Powerful server capabilities.
• Incremented productivity.
• Very cost effective and time saving.
• Software as Service known as SaaS.

A cloud is a combination of networks ,hardware, services, storage, and interfaces that helps in delivering computing as a service. It has three users :

1. End users
2. Business management users
3. cloud service provider

There are different data types in cloud computing like emails, contracts, images , blogs etc. As we know that data is increasing day by day so it is needed to new data types to store these new data. For an example, if you want to store video then you need a new data type.

Following are the different layers that are used by cloud architecture:

• CLC or Cloud Controller
• Walrus
• Cluster Controller
• SC or Storage Controller
• NC or Node Controller

The following platforms are used for large scale cloud computing:

• Apache Hadoop
• MapReduce

There are 3 layers in the hierarchy of cloud computing.

Infrastructure as a service (IaaS):It provides cloud infrastructure in terms of hardware as like memory, processor, speed etc.

Platform as a service (PaaS):It provides cloud application platform for the developer.

Software as a service (SaaS)::It provides the cloud applications to users directly without installing anything on the system. These applications remains on cloud.

Software As a Service (SaaS) is an important layer of cloud computing. It provides cloud applications like Google is doing. It facilitate users to save their document on the cloud and create as well.

It is also a layer in cloud architecture. This model is built on the infrastructure model and provide resources like computers, storage and network. It is responsible to provide complete virtualization of the infrastructure layer, make it look like a single server and invisible for outside world.

Cloud computing provides a on-demand access to the virtualized IT resources. It can be used by the subscriber. It uses shared pool to provide configurable resources. Shared pool contains networks, servers, storage, applications and services.