Dynamic global markets, higher customer expectations and changing compliance requirements continue to place new demands on organisations.  Yet most enterprises are hard-pressed to react quickly to these constantly changing business conditions.  IT systems must be more flexible and adaptive than ever before. 

According to Darren Roos, Software AG’s Sales Director, most enterprises have made huge investments to build the systems that manage the complex business processes needed to deliver a unique competitive advantage.  These large systems are now commonly called “legacy systems.”  And, while nothing compares to their performance and reliability, most were not designed to be highly flexible and adaptable.  
“The topic of how to match legacy systems with contemporary business demands is the proverbial Elephant in the Room at IT strategy meetings – convenient to avoid because the challenge is formidable and there seems to be no easy way of getting one’s arms around it,” says Roos. “A strategy that calls for rewriting or replacing existing legacy applications is sometimes presented, but the question often arises of whether it is even possible to recreate the valuable business logic and processes that have been developed over years of time to meet the organization’s unique needs.”
He says to achieve competitive advantage, an organisation must effectively align technology with business goals. Service-oriented Architecture (SOA) is helping enterprises do just that. It is an approach to application architecture in which the components (the business functionality) are well-defined as services using common interfaces.  SOA can help an organisation to improve productivity, agility and speed for both business and IT. SOA can result in user-friendly environments that hide the underlying IT complexity. And SOA also supports the processes that will make the business more competitive.
Roos maintains that once a decision is taken to move forward with SOA, the approach need not be all or nothing.’ SOA goals are best achieved in incremental steps.  An important starting point is to model the required business processes.  A process modeling initiative calls for technology that enables the alignment of people and IT systems with business strategy. Such technology, called Business Process Management (BPM), enables the organisation to model executable business processes, measure the results and improve the process.  
He says assuming that a particular process has been modeled and understood, the next task is to define the services that will feed into that process. One challenge is determining how fine-grained (like sand) or coarse-grained (like pebbles) each service should be. The opportunity to reuse a given service in a variety of processes will help in defining its level of granularity. The beauty of SOA is that it is possible to have a coarse-grained service that makes use of several fine-grained services. A BPM tool can assist in defining all the services used in a given process.
“After these first steps, it is time to determine whether to reuse existing applications or build new functionality from scratch,” Roos says.  “The good news is that much of the functionality needed is probably already available within the company’s legacy system code.  It is possible to harness the significant investments already made in legacy systems by opening them up and turning them into an information “reservoir” for an SOA to draw from.  This process is called service enablement.”
He notes that even after business processes have been analysed and optimised, and existing legacy systems service-enabled, some elements of functionality required by the business will likely still be missing.  A highly productive service-oriented development environment is needed that empowers developers to rapidly generate new business functions.  Speed and quality are two critical aspects of application design that are often in conflict, so the new development environment should take both elements into account.
With services in place – either newly created or drawn from legacy systems – an Enterprise Service Bus (ESB) will allow the “orchestration” of fine-grained technical services into powerful new business services that operate at the right level of granularity.
Many companies have business data distributed in “silos” throughout the organization – including within legacy systems.  Yet business users would like to somehow access these disparate data sources using business terms.  This requires Information Integration technology that uses services to dynamically aggregate data based on the user’s needs and familiar business terminology.  By reconciling differences between business concepts to reduce complexity, business users can access composite “views” of information that actually resides in different places.
Finally, technologies such as Rich Internet Applications (RIA) can create an easy-to-use browser interface that blends services from legacy systems with new services.
Roos concludes, “Changing business conditions means that organisations must choose to implement flexible and adaptive IT strategies.  An effective SOA strategy can provide a practical way to face one of the largest hurdles in this process – making valuable legacy systems a vital part of the new conversation rather than the Elephant in the Room, destined to be ignored until the next meeting.”