No more “On-premise vs SaaS”, please!
On-Premise is an architectural deployment decision (On-premise vs. Cloud). It defines where your software would physically be deployed, and the access and connectivity options available to you. It’s a decision that has to be taken in context of the rest of your enterprise architecture landscape and your long-term design strategies.
Software-as-a-Service (SaaS) is a licensing model and, if you are comparing it with anything, it would be with Perpetual Licensing which has been the traditional IT licensing model for many years. This relates to how you are going to pay for using the solution: Pay a large sum (usually) up front as capital expense (Cap-Ex), and you own a perpetual license to access the solution forever. It is then your choice if you also pay and an annual support fee as an Operational Expense(Op-Ex). But the license to use the software is yours forever. Alternatively, in SaaS, you pay a much smaller amount per user/per month (all Op-Ex), which is flexible as your requirements change. In the SaaS model, you don’t actually own any licenses you are effectively “paying rent” only for as long as you are using the solution. This has nothing to do with where the solution is physically deployed.
And just to confuse the definitions even further, SaaS is also sometimes used to refer to the responsibility for administering the systems and supporting the solution. Typically, in a perpetually licensed environment, the license owner is responsible for the administration of the solution (or a third-party, if Application Management has been outsourced). In the SaaS model, the administration burden typically lies with the solution provider, not the organisation paying for the services.
The confusion has come about by the fact that, most commonly, perpetually licensed software tends to be deployed on-premise and managed by the license owner, whereas SaaS software tends to be deployed on cloud and administered by the service provider. But it does not have to be that way: Theoretically at least, there is nothing stopping you from deploying your perpetually licensed software on a private cloud, instead of on-premise. There is also nothing stopping you from negotiating a SaaS payment model with your software vendor, even if the software is deployed on-premise.
So the question of “On-Premise vs SaaS” usually implies: “On-Premise, perpetually licensed, self administered VS Cloud hosted, Pay-as-you-use, provider managed”.
And I’m not even going to start talking about what this implies for private vs public vs hybrid clouds and Single instance vs Multi-tenant architectures, which are also often lumped under the “SaaS” moniker, even though they have nothing to do with SaaS.
I know the differences are semantic but, as Information Management professionals, we have a duty to be clear about the terminology we use. Our clients have more than enough to be confused about, we don’t need to make it any worse.
P.S. As my good friend and fellow pedant, Chris Walker reminded me, the correct term is “On-Premises” not “On-Premise”. He is right of course. There is no excuse for bad English either! 🙂