IaaS, PaaS and SaaS. What’s the difference and why are they important?

These days, it’s almost impossible to read any kind of technology publication without coming across the word “cloud computing” multiple times. Often, these cloud discussions come mixed up with strange acronyms such as IaaS, SaaS, PaaS and others.

My aim in this piece is to clarify some of the leading “aaS” acronyms you may come across.

SaaS – Software As A Service

The most common form of cloud computing would be Software-as-a-Serivce, or SaaS.As the name would imply, Software-as-a-Service is (usually) software that doesn’t need to be installed on your local machine. Instead, you access a remote system which hosts the software for you.

In essence, any interactive web site could technically be considered a SaaS application.  When you access Gmail, you don’t get access to the Gmail source code and you don’t need to install Gmail on your computer. You simply access a web site, log in, and start using the application.

Video players – which formerly had to be installed – were replaced by YouTube’s SaaS video player.

Although “ideally” SaaS should never require local software installations, you may sometimes need to install a “client” which serves as an interface to the remote server which performs most of the work. For example, you may need to install a small application to access a Virtual Desktop Interface which resides on a remote server. In this context, even your web browser could be considered a client application which must be installed to access your SaaS apps.

The important thing to keep in mind with SaaS is that the critical functions of the service are performed on the SaaS company’s remote servers.. and not on your local machine.

Today, there is a growing preference amongst developers to release business productivity applications through browser-based interfaces. This ensures that systems can be accessed through any OS, whether Windows, Linux, Mac, Smartphone or Tablet.

PaaS – Platform As A Service

Platform-as-a-Service is a slightly more complicated embodiment of cloud computing which is more suited to developers. In its essence, PaaS providers host development environment featuring a number of libraries and tools which can be used to develop and deploy custom cloud-based applications. PaaS simplifies development by eliminating the need to host and manage the underlying infrastructure which supports custom applications.

IaaS – Infrastructure As A Service

Infrastructure-as-a-Service is one of the fastest-growing flavors of cloud computing within the business space. It is also based on a very simple concept, which has wide-ranging implications and benefits for IT administrators.

Most servers today are hosted in “virtualized” environments. In other words, a single server may contain dozens of software-based “virtual machines” which trick the operating system in to believing that it resides on physical hardware. Virtualization offers a number of core advantages in terms of efficiency, cost-saving, disaster recovery and deployment. (But that’s a discussion for another article)

With the IaaS model, you simply host a virtual server in a remote third-party datacenter in the same way that you would host a virtual machine on your own hypervisor inside of your datacenter.

IaaS is attractive to small businesses because building your own server room can be expensive, and these IaaS facilities have lots of features which would simply be cost-prohibitive for smaller companies.

Larger companies also like IaaS because it allows them to obtain temporary on-demand capacity in the event of a sudden short-term spike in systems requirements. This is a much more cost-effective option than simply purchasing new hardware to fill a temporary need.

And there we have the 3 main flavors of cloud computing: IaaS, SaaS and PaaS. You’ll see other versions of this acronym such as BaaS, CaaS, DaaS, FaaS, ect… but these are usually more of a marketing ploy than anything else. If you break it all down to its essential elements, most “aaS” acronyms can be placed intro one of these 3 broad categories.