Cloud computing enables ubiquitous, convenient, on-demand access to a shared network of computing resources such as networks, servers, applications, services and storage that can be easily made available with minimal management and interaction by the service model provider.Cloud computing consists of three service models - Iaas, PaaS and SaaS and four deployment models - public cloud, private cloud, hybrid cloud or community cloud. Service models IaaS (Infrastructure as a Service): The capacity that is provided to companies using this type of model includes data processing and storage, networks and other fundamental computer resources that allow the implementation and execution of arbitrary software, which may include operating systems and applications.Companies that use this service have control over the operating systems they use, storage and installed applications, and possible control over selected networking components such as host firewalls. PaaS (Platform as a Service): Allows the implementation in the cloud infrastructure of applications created or acquired by companies in programming languages, libraries, services or other tools that are supported by the supplier of the model.The companies that contract the service have control over the installed applications and possibly the configuration settings of the location where these applications are hosted. SaaS (Software as a Service): This type of model allows companies to use the supplier's applications, operationalized through a cloud infrastructure. Accessibility to the applications is possible from different devices, through for example, web browser or program interface.Management and control of the cloud infrastructure - network, servers, operating systems, storage or individual application functionality (with the exception of configurations for applications with limited users) - is the responsibility of the service model provider. There are different types of cloud - public, private, hybrid and community - all of which aim to provide easy and scalable access to computing resources and IT services. Deployment models The public cloud is an outsourced service that can be managed, operated and owned by different types of companies or a combination of them, and provides technology resources, such as servers and storage for use by the general public. Private cloud refers to cloud resources used exclusively by a single company and comprises multiple users. Ownership and management of the cloud can be the company itself, the service provider or a combination of the two. The hybrid cloud refers to the combination of two or more clouds - each cloud remaining unique, but connected through technology that enables the transfer of data and applications. Community cloud infrastructure is available for exclusive use by a 'group' of people from organizations that share, for example, the same mission, security or policy requirements. The community cloud can be managed, operated and owned by one or more organizations, outsourced or a combination of both. Naturally, different businesses will not have the same type of IT needs, which makes cloud storage an effective solution when it comes to business scalability. The number of 'users' can increase or decrease as the business or organization needs over time, and storage capacity can easily be increased without investment in physical infrastructure.