Platform as a service

Platform as a service
In the recent years, we have been hearing a lot about Service Oriented Architecture. It started with Software as a Service (SaaS), where companies provided the applications in form of services over the internet instead of desktop applications. With this, it was not required to install the application on a system before they can be used. Then this service paradigm proceeded to Hardware as a Service (HaaS), where vendors provided services to use Hardware. This is also known as Infrastructure as a Service (IaaS) and the services delivered include servers, network equipment, memory, CPU, disk space and data center facilities etc.
But, for any application, it is the combination of Hardware and Software that is required. SaaS and HaaS are services catering to these needs separately but the latest concept that could address both software and hardware requirements is a concept, called Platform as a Service (PaaS).
PaaS is the delivery of a computing platform and solution stack as a service. Computing Platform is some sort of hardware architecture or software framework (including application frameworks), that allows software to run. A solution stack is a set of software subsystems or components needed to deliver a fully functional solution, e.g. a product or service. PaaS goes further with the provision of a software development platform at the top of solution stack.
PaaS offerings typically include workflow facilities for application design, application development, testing, deployment and hosting as well as application services such as team collaboration, web service integration and marshaling, database integration, security, scalability, storage, persistence, state management, application versioning, application instrumentation and developer community facilitation. These services are provisioned as an integrated solution over the web. One of the products from Microsoft which enables PaaS is Windows Azure Platform. This article is intended to provide an overview of Windows Azure. Read on to familiarize yourself with Windows Azure…..

References:
Windows Azure Product Page
Introduction to Azure