cloud computing

Cloud computing?is the on-demand availability of?computer?system resources, especially data storage (cloud storage) and?computing power, without direct active management by the user.?Large clouds often have functions?distributed?over multiple locations, each of which is a?data center. Cloud computing relies on sharing of resources to achieve coherence and typically uses a pay-as-you-go model, which can help in reducing?capital expenses?but may also lead to unexpected?operating expenses?for users.

Cloud computing has a rich history that extends back to the 1960s, with the initial concepts of time-sharing becoming popularized via Remote Job Entry (RJE). The "data center" model, where users submitted jobs to operators to run on mainframes, was predominantly used during this era. This was a time of exploration and experimentation with ways to make large-scale computing power available to more users through time-sharing, optimizing the infrastructure, platform, and applications, and increasing efficiency for end users.In the 2000s, the application of cloud computing began to take shape with the establishment of Amazon Web Services in 2002, which allowed developers to build applications independently. Other milestones during this decade include the introduction of Amazon's Simple Storage Service (S3) and Elastic Compute Cloud (EC2) in 2006, Google's release of the beta version of Google App Engine in 2008, and NASA's development of the first open-source software for deploying private and hybrid clouds the same year .