Difference between SaaS,PaaS and IaaS
IaaS (Infrastructure as a Service) :
Provides the infrastructure as virtual machine, storage ( Hard Disks), Server, Network, Firewalls, Load balancer etc for the service. This is based on the cloud computing which provides the facility to store, deploy and run your application in virtual environment. Cost of IaaS depends on the use of infrastructure. Third party manages all your applications and they do billing according to your use. There are many service providers which allow you to install a virtual server on their IT infrastructure. For example : Amazon EC2, Windows Azure, Rackspace, Google Compute Engine where you can develop and run your applications.
PaaS (Platform as a Service) :
Provides the complete platform as programming language execution environment (as java), operating system, database (as my sql, oracle), web server (as tomcat), to develop your application. For example Google App Engine where you can develop your code and run globally your application. Very useful for the developers where they can deploy their applications and check the performance and behavior. Developers can develop their applications and customize on minimum cost and without worrying about application management. This is also based on the cloud computing.
SaaS (Software as a Service) :
Provide the access of the application. Application can be accessed by the url and by providing the access authentication if needed. For example accessing your email is one of the applications which is based on SaaS model where you access the service by providing only the url in address bar in the browser. Also if needed you can provide the login credentials to access other features or to view your mail. In SaaS we don’t have to worry about application hosting or management or any infrastructure. All other things are done by IaaS and PaaS. SaaS is mostly used by customers who only bother about accessing the application. This is also based on cloud computing. Most of the applications are based on web services and can be accessed through browser. SaaS uses the Web to deliver applications that are managed by a third-party vendor and whose interface is accessed on the clients’ side.