It all starts here: trying to explain the different flavors of cloud computing to some not-too-IT-immersed folks… Truth is, if you’ve ever tried to do this, you quickly realize that it’s a bit of a challenge as you first have to cover the basics of SaaS, PaaS, and IaaS! And (another truth be told), I would not say these are totally clear concepts yet and they will probably never be, so in order to explain well, you have to make things simpler than they really are. If you disagree, please comment on this post!

So the best way I’ve found to explain these 3 layers of aaS (namely Saas, PaaS, and IaaS) to the non-IT folks out there is with the help of visuals, in this case, an Image + Short definition of my own + Slogan + Examples.

My image representing Software is a pyramid, where on top, stands the end user, below him are a couple of developers developing the app that the end-user is using. Below these developers is an IT crowd made up of system admins and other operation folks making it possible for developers to develop and then deploy their apps! Ok, in the real world the pyramid should be inversed. It should have more users than developers, and more developers than ops (at least most of the time), but I like the image like this. If ops fails to keep the infrastructure solid, both devs and end-users collapse; if devs fail, end-users collapse.

A bit abstract, perhaps? Not a good drawing? And, maybe you’re wondering what this has to do with Software as a service?

Let me go straight to the explanation by jumping to definitions.

SaaS or Power to End-Users

As mentioned, standing at the top of the software pyramid is the end-user, he is the king, per definition. His experience is what makes software great (or not).

SaaS, which stands for software as a service is all about serving him, in the cloud. SaaS is about providing our end-user “king” a useful application in the cloud without having to deal with the technicalities of its development and its infrastructure.

Want a good example? Well, Salesforce initially invented it! Their CRM application, designed specifically for the sales force, freed the end-user of the burden of having to think about software installation, configuration or even updates. It enabled a consume as you go environment, giving Power to End Users! Talking about cloud content management, we can look at WordPress.com and see how the nice folks at Automattic have managed to deliver this as a service without having to dive into the nuts and bolts of the famous blogging software of the same name!

PaaS or Power to Developers

Let’s jump one level lower and discuss PaaS, which stands for Platform as a Service. In this realm, it’s not about end users but developers. PaaS brings Power to Developers. Here, they no longer need to think about the infrastructure, which comes to them in the Cloud, simple, straightforward, and on demand! Example? Well, here again, Salesforce did it well when releasing Force.com. But other kinds of examples of this method of implementation can be found at CloudFoundry. In another flavor, what we do at Nuxeo, with Nuxeo Cloud, tackles the same concept—enabling developers in the cloud to build their apps in a simpler way.

IaaS or Power to Sysadmins

And going down one more level, to the foundation, we hit the IaaS floor. This is giving Power to Sysadmins. Developers will still develop as usual, they will use “servers”, “database”, “file systems storage”, “web servers”… all these tangible pieces of the system stack will not be hidden & abstracted from them. This also means we still need sysadmins to care for these systems, as we all know developers should focus on the application layer (ok, I know this is old school and I know there is some overlap between developers and sysadmins with disciplines like Devops, but let’s not get too far into that, otherwise my explanation will be hard to digest…) IaaS is simply this: it’s all about giving more power to ops!

This one is the easiest to provide an example for! Amazon with its AWS business is the obvious example, as well as a pioneer and by far the leader in this sector!

Cloud is all about Apps, Platforms and Infrastructure as a Service

But isn’t PaaS and IaaS as much about software as SaaS? Definitely. Hence, if you ask me, the need to rename the top layer to AaaS (Application as a Service). After all, Salesforce.com, probably the inventor of this layer itself has this strong and purposeful slogan: “No Software”…its about applications here, not about software, wherein A/P/IaaS all fall into the bigger SaaS basket. And now I’ll just wait for the evil techie who introduces API as a Service… but I should probably stop here!

I hope you enjoyed this short read. Honestly, I am not an expert of cloud computing terminology (I will leave this to the analysts) and I am neither a huge addict of boxes and categorizations, but obviously there are very grey areas between these layers. But as this subject keeps coming up in conversations with colleagues, friends (and soon…my parents? um, thank you Apple for introducing iCloud…), I thought it was high time to devote some space to it on this blog. I’m happy, as ever, if anyone likes it and, of course, if you want to comment and discuss, feel free to type below…