People all around the world have heard these terms SAAS, PAAS and IAAS and want to know the difference. I also wanted to do the same and hence set out Googling, asking and reading a lot. Finally, I think I got a fair idea of the difference and hence this post.
- Image courtesy cloudstrategies.com
What we basically need to understand is the basic definitions of Compute, App Framework and Biz Logic.
Compute – The term Compute in terms of Cloud Computing means the Customer’s physical hardware needs and all the other problems associated with managing the hardware for the client. If I try to find an analogy with PC’s it will be like you are given a blank PC with OS of your choice, RAM and DISK space of your need with ability to scale. This consists the computing and storage of the computer. An IAAS provider will give you all this(compute) and some other facilities like easy ways to take backups(Back up choices are not the best as far as the Cloud Vendors are concerned. They mostly don’t provide file by file backup. Instead, a disk image based backup is provided).
App Framework – The application framework consists of providing the facilities of support the complete life cycle of building and delivering web applications and services. It is in a way an environment which helps you develop faster with the help of some interactive tools without giving you the extreme flexibility of the UNIX console. A PAAS will consist of “Compute and App Framework“. Facilities provided include things like database management, security, workflow management, application serving, and so on. In an analogy with Web Development, say you have an Apache Server installed on the server and you are told your files to a particular folder and you are good to go. If you donot upload anything, you will get a standard URL and opening it will say “You Website is Ready to USE.” Remember, your good old c-panel you get when you start building your first website. When such a panel is deployed on the Cloud with scalability and on demand payment services, it is roughly a PAAS. The difference comes in the way the various parts of the application interact with each other. Unlike a cpanel it happens through API calls in a PAAS.
- Source: katescomment.com
The above diagram shows the various service layers in the Cloud. However, I and my friend Swapnil had a good round of debate on whether Operating System should be a part of the Infrastructure as most of the IAAS provider give out their services along with an OS.
Biz Logic: Business Logic is the logic behind the customized solution which fits your need. A SAAS will provide you with “Compute, App Framework and Biz Logic“. However, you will not have much flexibility on the customizations you make. Gmail is an ideal example of SAAS, where you get certain functionalities are inbuilt and some can be customized by you according to your needs. You create your own labels according to your needs and your friend can create his own. It will however not let you deploy an application over Gmail. You lost that flexibility with IAAS and PAAS. You have one business logic of emailing solved for you in the way Google thinks best. You get new features only when lots of other users of the SAAS also ask for it and Google decides it is worth.
I have tried to put up some differences between SAAS, PAAS and IAAS. There is a definite overlap between these services in the way various vendors provide it. Let me know what all can be added to this definition in either the quora question I put up or in the comments.
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