Software as a service (Saas), Infrastructure as a service (Iaas) and Platform as a service (Paas) are used very often in different context for describing different technologies services in modern information technology.
Let me make some order about these definition using about the products available on the software market.
I’m reading a lot of articles where it’s using these definitions and, sometimes, I find out these not so straightforward with the common meaning of these technologies. That doesn’t mean to have a poor knowledge of the argument but rather the borders of these definitions is not so sharp as we’d like to be.
I’m not so arrogant to give you a complete, final definitions of these so I made a choice to illustrate them using a market leader products of these technologies (at least in my opinion).
So, let’s start illustrating Saas technology:
The common definition for Saas is referring to a software which provides a service on demand. Example of these are the WebMail (Gmail), e-commerce (ebay) and booking service (Expedia).
The follow definition, Iaas, looks like that:
When you’re speaking about Iaas you’re speaking about a platform which provides hosting, load balacing, network connectivity and storage. In one word you might speaking about the cloud as Windows Azure and Joyent or Amazon Web Service.
The last definition we’re going to talk is Paas.
This is the definition which makes more confusion after reading a different interpretations. The shared definition of it is a service which provides a platform for others to use it. Typical is a service that provides operation system and some framework for developing your solution.
We can talk about Paas when we’re speaking of OpenShift (a Red Hat’s solution) or WordPress personal web site. The same could be said whether we’re using Google application engine that provides a framework definition.
That’s all. Are you still confused? I hope you’ve enjoyed this definitions by examples to have a clearer idea the next time you’ll listen, or read, these definitions.