What is this "Cloud" thing - Part 2

SaaS - Software as a Service - This is the situation when software is not loaded on your computer. For example, if you use Google Apps, like Docs, Sheets, Calendar, or even Gmail, those programs are loaded on Google's servers, and you just use them. A big advantage is that the programs exist all in one place, therefore updates and upgrades are easy to do.

IaaS - Infrastructure as a Service - This is closest to the current term "Cloud". As in Part 1 of this series, Public or Hybrid clouds is where someone else deals with the hardware, etc. In this case, they "present" you with your IT infrastructure (or a piece of it), treating it like a service. Hense the name IaaS. It's pay as you go Infrastructure that someone else controls and maintains.

PaaS - Platform as a Service - This takes the next step. The outside vendor controls more of the environment. Not only the hardware, but the main databases, security, etc. You control less.