The Internet and trade literature today are rife with definitions of SaaS. It seems everyone feels a need to trot out their favorite variation on the theme, as if rearranging the words one more time will somehow make matters clearer, or turn non-believers into believers.
Confusing matters further, the related trend of “cloud computing” is often referred to in the same breath, often interchangeably, which leaves the impression that they are the same thing. We think nothing could be further from the truth, but more on that later.
In the mean time, rather than adding to the existing plethora of definitions, we are happy to provide the meanings of these two key terms by borrowing from NIST—perhaps one of the few parties currently writing on the subject without “a dog in the fight.”
Herewith, a condensed version from their recent publication on the subject:
So far, so good. The cloud is a concept and SaaS is about delivery.
Software as a Service | |
A model for enabling available, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.[1] | A delivery model for cloud computing, provided to the consumer to use the applications running on a cloud infrastructure and accessible from various client devices through a thin client interface such as a Web browser. The consumer does not manage or control the underlying cloud infrastructure, network, servers, operating systems, storage, or even individual application capabilities. [2] |
However, we feel that there’s an important technical footnote to add to this common understanding, and that’s the notion of multi-tenancy.
The core idea of multi-tenancy is that “all users and applications share a single, common infrastructure and code base that is centrally maintained.”[3] Just as a building’s structural architecture will differ depending on whether it is designed for a single occupant or multiple tenants, so too will a software system’s design differ depending on whether it is intended to be used by a single “tenant” or multiple tenants. In this model, cost savings are achieved both through commonality of hardware resources, as well as sharing licensing and operating expenses more efficiently across a large population of users.
Multi-tenancy stands in sharp contrast to the practice of simply deploying a stack of client-server systems in a data center and calling it a hosted service. In its “Four Level SaaS Maturity Model,” Microsoft categorizes this approach as the “lowest level” of SaaS maturity, or roughly equivalent to the “traditional application service provider (ASP) model of software delivery, dating back to the 1990s,” which “offers few of the benefits of a fully mature SaaS solution.” [4]
This stack-a-box or hide-the-server approach to providing remote software services is simply a case of what many observers call “cloud envy.” And it has the net effect of trapping service providers and customers into a costly cycle of maintenance and replacement. Doing the math, it becomes obvious that the overall solution is still saddled with the same cost structure as if it were located at the customer site. Except for the fact that someone else is managing the system, the stack-a-box approach is no different than the legacy approach to application ownership.
Next week, with this background in mind, we take a deeper look at the current state of electronic security systems, and why they are ripe for improvements through SaaS.
-Steve Van Till
[1] National Institute of Standards and Technology, "Computer Security Resource Center
[2] ibid
[3] Salesforce.com, "Multi-Tenant Plaform," 5 Sep 2009, salesforce.com, 5 Sep 2009 http://www.salesforce.com/au/platform/why-ondemand/muti-tenant-platforms/.
[4] Microsoft Corporation, "Architecture Strategies for Catching the Long Tail," April 2006, Microsoft Developer Network, 1 October 2009 http://msdn.microsoft.com/en-us/library/aa479069.aspx.
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