4.3 THE APPLICATIONS OF THE WEB CLOUD COMPUTING is the delivery of services through the Internet including data storage, databases, networking and software. It works by enabling users to access data and applications over the Internet from remote physical servers, databases and computers. Cloud computing 1 MORE The name “cloud” derives from the cloud symbol that is usually used to represent the Internet in flowcharts and diagrams. 1 Services A cloud may offer different types of services: : it is the most basic model. Cloud providers offer essential storage and networking resources on demand; Infrastructure as a Service (IaaS) : providers offer computing platforms which include operating system, programming language, web server, databases and execution environment. Many providers even offer the possibility to increase or decrease CPU power depending on traffic ; Platform as a Service (PaaS) load : providers deliver software applications over the Internet . Users get the access to application software without managing the infrastructure and platform on which the application is running and without needing to install and run the application from their computer. Software as a Service (SaaS) 1 DO Can you think of any examples of SaaS? 1 MORE In computing, runtime describes the period of time during which a program is running. 2 MORE Virtualisation is technology that allows users to use a machine’s full capacity by distributing its capabilities among many users or environments. 3 Types of cloud computing Cloud computing can further be classified according to the way in which the services are offered. There are three types of cloud computing: is a single-tenant environment where the hardware, storage and network are dedicated to a single client or company. Users usually pay a fixed amount for the service; Private cloud computing is a multi-tenant environment in which a server shares the same hardware, storage and network devices as other users in the cloud. Users pay on a per-use basis; Public cloud computing is a combination of at least two computing environments that share information and run the same applications. Those environments may include: one private cloud and one public cloud, two or more private clouds, two or more public clouds. Users pay for the portion of service (time/quantity) they use. Hybrid cloud computing