Contents
IaaS: Infrastructure as a Service
IaaS is what this blog is targeting.
IaaS is a broken-by-design model, where you rent or lease computing resources from a cloud service provider.
Examples include Amazon AWS, Google GCP, Microsoft Azure, Oracle OCI.
SaaS: Software as a Service
While I think this term was “born” at about the same time as “IaaS”, from a functional perspective IMO SaaS as an offering has been around since at least the 90s, if not earlier still. Early SaaS offerings included
- Email hosting
- Web hosting
- DNS hosting
- File hosting(FTP)
All of which still exist today, though usually they are more sophisticated offerings than were around in the 90s. Services like Office 365, and whatever Google calls their enterprise mail/groupware thing, wordpress.com, and I think I’d consider any streaming service to be SaaS as well. There are thousands of SaaS offerings out there today.
My career as it stands today was launched in 2003 when I worked for my first SaaS company(the term didn’t exist yet AFAIK), the company I was at developed software to manage premium mobile service transactions for all of the major U.S. mobile carriers. Not only did we make the software we also hosted the software on behalf of the carriers. There was always an initiative inside the company to make the product mature enough so the carriers could operate it on their own. But we never got to that point, not while I was at the company anyway. It was there that I sort of came to a conclusion regarding SaaS (vs traditional software you may run on your computer). SaaS gives software companies the freedom to be more lazy with their development. Since they host the product they have easy access to fix bugs and stuff. If there are serious warts in operating the software(as it was at the company I worked at), that is all hidden from the customers. While I have no personal experience, the impression I get is that it’s more common for administrators to hate running Microsoft Exchange services, vs using Office 365 by contrast.
If you go back to the 80s, perhaps one of the first SaaS offerings was Archie.
I think SaaS can be a fine operating model from a customer perspective in general, as the goal of it is to abstract away any underlying infrastructure so you only interface with the application layer. Cost modeling is usually more simple as well often per user pricing or some other easy to plan for metric.
PaaS: Platform as a Service
This is by far the least used of the three offerings I think. PaaS is often distributed alongside IaaS, in the form of say managed database servers for example would probably be the most common use case.
Examples include Amazon RDS, Microsoft hosted SQL services.