This concept of computing is in growth. Every firm today transfer their hardware and software in cloud. It is cheaper and it brings more mobility to a firm. Basically your office can be anywhere in the world with access of internet. This saves company money for buying expensive hardware and software licences and of course people who need to maintain all of this. If you need this month more hardware resources just acquire them, and when you do not need them any more just release them. Although cloud computing has changed over time, it has been divided into three broad sevice categories: infrastructure as a service (Iaas), platform as a service (PaaS) and software as a service.