Platform as a Service
Platform as a service (PaaS) is defined in its name, it is the platform that hosts applications provided in software as a service. For example, Google App Engine is a PaaS that hosts Google Apps and a multitude of other softwares-as-a-service. PaaS provides all the infrastructure needed to run applications over the Internet, and is delivered in the same way as a utility like electricity or water. Users simply “tap in” and take what they need without worrying about the complexity behind the scenes. And like a utility, PaaS is based on a metering or subscription model so users only pay for what they use. Examples of PaaS are Google App Engine, Force.com and Heroku.
Software as a Service
Software as a service (SaaS) is apply referred to as software “on demand.” SaaS solutions offer subscription-based access to enterprise applications that service a vast range of functions and departmental needs and are hosted securely in cloud data centers. Many, if not all, of the enterprise products offered by Google and Salesforce offer prime examples of SaaS solutions.
Organizations that operate on SaaS solutions such as Google Apps is no longer burdened with the time-consuming and costly task of managing software updates, security patches and a host of other administrative duties for on-premise software solutions. SaaS ensures that these tasks are managed quickly, efficiently and affordably on the back-end so that IT teams have more time to work on projects that propel the business forward.
Infrastructure as a service
Infrastructure as a service (IaaS) enables businesses to move information from on-site servers into the Cloud. It provides a remote virtual hosting server for file storage, as it enables a user to save all of their file types in a virtual host and retrieve them from anywhere with an internet connection. Examples of IaaS are Google Compute Engine, Google Cloud Storage and Google Big Query.