Cloud services

The most widely used definition of “cloud computing” is the one published by the US National Institute of Standards and Technology (NIST), according to which, “cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g. networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction”. The NIST document defines three service models: Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as a Service (IaaS), and four deployment models: public, private, community and hybrid cloud environments, although it should be borne in mind that new models are being developed all the time.