INTRODUCTION AND BACKGROUND CLOUD COMPUTING deals with the storage and access to data and programs on the Internet without using the computer's hard disk. Cloud computing doesn't deal with your hard drive. Cloud computing has been around for many years. This was an evolution that began in the 1950s with mainframe computing. In this case multiple users were only able to access a central computer via dumb terminals, whose only function was to provide access to the mainframe. As a matter of cost efficiency, it was not practical for an organization to purchase and maintain one for each employee. So, providing shared access to a single resource was the economically sensible solution for this sophisticated technology tool. Later, in 1970, the concept of virtual machines was invented. Using VMware virtualization software, it was possible to run more than one operating system simultaneously in an isolated environment. This virtual machine operating system took the shared access of the 1950s to the next level, allowing multiple distinct computing environments to reside in a single physical environment. In the 1990s, telecoms arrived and began offering virtualized private network connections. They only offered single, dedicated point-to-point data connections. In this case, telecommunications companies were unable to provide users with shared access to the same physical infrastructure. The following list explains the evolution of cloud computing:1. Grid computing: Using parallel computing we solve big problems.2. Utility computing: computing services are offered as a pay-as-you-go service.3. SaaS: Network-based subscriptions to applications.4. Cloud computing: access to IT resources dynamically provided anytime, anywhere as a service....... middle of paper ...... user data worries about data possibly being corrupted by viruses and malware. There are companies that take measures that provide customizable spam filters and email encryption among the security measures.2. In Cloud computing, privacy is one of the main factors that could lead unauthorized users to access information in the cloud. To prevent this from happening, companies offer password protection and data encryption technology.3. Users are controlled by cloud computing. This includes how you pay for the service, where and how you use the service, and other factors. Users are totally dependent on company updates and backups. If servers stop working, users have the possibility of losing all stored information.4. Internet is not yet available worldwide. If the area you are in does not support the Internet, you cannot save and download from the cloud.