The definition of cloud computing is presented, its characteristics, different cloud services and various platforms that are used in cloud computing, often considered the successor of grid, cluster and, mainframe computing.
: Cloud computing now easily tops any list of topics in computer science because of its far reaching involvements in many areas in computing, especially Big Data. Moreover, It is a one of the most emerging technology due to the provision of various computing infrastructure and services. Cloud computing has evolved through a number of phases that include mainframe computing, cluster computing, and grid computing, parallel computing, distributed computing and utility computing. Cloud computing is often considered the successor of grid, cluster and, mainframe computing. Cloud computing is the delivery of many services through the Internet. These resources include tools and applications like databases, infrastructure, platforms, data storage, servers, networking, and software. Many people and businesses use cloud for a number of reasons including cost savings, increased productivity, speed, efficiency, high performance, scalability, high computing power and security. This paper presents the definition of cloud computing, its characteristics, different cloud services and various platforms that are used in cloud computing.