Cloud platforms allow accessing of computing resources over a network. Services are divided into Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). Popular cloud providers include Amazon Web Services, Microsoft Azure, Google App Engine, and Hadoop. Amazon EC2 offers IaaS through virtual machines created from Amazon Machine Images and configured with varying resources. Amazon S3 provides scalable object storage through a hierarchical bucket and object model. Hadoop is an open-source software platform that allows processing vast amounts of data across a distributed cluster in a reliable and scalable manner.