Turning Software into a Service

I n 1999, the Pennine Group—a consortium of software engineering researchers from the University of Durham, Keele University, and the University of Manchester Institute of Science and Technology—asserted that continued development of new architectural styles based on constructional forms such as objects or components would not advance the software field. Rather, they foresaw a future in which developers take a radically different view of how software delivers its functionality to users. We have explored the software as a service (SaaS) concept through several small-scale experiments. This concept envisages a demand-led software market in which businesses assemble and provide services when needed to address a particular requirement. The SaaS vision is a vital contribution to current thinking about software development and delivery that has arisen in part from initiatives in the Web services and electronic-business-communication communities. SaaS focuses on separating the possession and ownership of software from its use. Delivering software’s functionality as a set of distributed services that can be configured and bound at delivery time can overcome many current limitations constraining software use, deployment, and evolution. Such a model would open up new markets, both for relatively small-scale specialist-services providers and for larger organizations that provide more general services. In addition, service provision could include the dynamic creation and development of entirely new services that use existing ones. The “Sample SaaS Scenario” sidebar shows inherent SaaS ideas in the context of a company helping with an overseas property purchase. This approach lets the set of services a business uses evolve without any user intervention as that business and its context change. Also, the key knowhow involved is not who provides services, necessary though that knowledge is, but what service a transaction requires at any particular point, along with negotiating suitable terms for its use. Selecting and binding the means of providing an appropriate service can therefore be performed dynamically, on demand, through ultra-late binding.