With any XaaS variant, ‘as a service‘ is the common denominator between three. XaaS basically means offering customers physical assets rather than a physical purchase. Those physical assets can be anything from airplane engines to music to IT systems. SaaS vs PaaS vs IaaS refers to the world of IT servers, storage and networking. So, what does that really mean?
What is IaaS?
With IaaS (Infrastructure as a Service) customers do not buy IT hardware, they pay a monthly fee for the use of the servers, storage and networking. This means the customer isn’t responsible for the maintenance upgrades and support of those assets.
What is Paas?
PaaS (Platform as a Service) is the next level of responsibility; the customer has less responsibility for assembling the IT infrastructure into a platform which allows the customer to install applications and to manage data. PaaS would include the operating systems (OS), middleware and the runtime/virtualization environments.
What is SaaS?
SaaS (Software as a Service) is an application built upon IaaS and PaaS, it is where customers can start using the application form day one without any need for any installation at all. This may seem like a small step but SaaS can, and often is, built on micro service technology. Micro service technology allows a piece of software to automatically scale. The more the user uses the application the more IT resources the micro service will ask for and vice versa.
This theory means that a SaaS micro service could scale from 1 user to 1 million users without the need for any new servers, storage or networking. This in turn allows SaaS businesses to offer customer new types of business models including freemium, metered usage or even value-based pricing.
The one thing I haven’t talked about is where do containers fit into this picture? That’s for another time.