Enterprise Executive 2017: Issue 2 : Page 53

New web and mobile applications can be built that use the refaced interface for business logic and data hosted in the legacy application. Refacing an application enables people with web browser skills to easily acclimate to the legacy application with minimal training. One example of a product that provides refacing is IBM’s Rational Host Access Transformation Services. Brokering Another form of porting is converting from one programming language to another while still maintaining the business logic. There are tools that purport to do this business logic porting, but be very cautious about using code generators for anything but very specialized cases since they rarely produce performance optimized code. Rewriting The next step up from refacing is to provide a separate middle tier that allows you to use legacy applications in innovative ways through a broker technology. Brokering differs from refacing in that business logic and flows can be embedded in the middle tier for new web and mobile applications. Instead of one-to-one refacing to legacy applications, there can be a single front-end application that uses many legacy application interfaces on the back-end to provide a richer, more intuitive presentation to the end user. Brokering can also be used to allow programmatic front-end interfaces to use legacy interfaces that were originally intended only for people to use. There are many examples of brokering middleware that can be used to provide this function. Almost any good enterprise service bus (ESB) gives you the ability to broker legacy applications. Porting Sometimes the problem is not so much the actual application, but the platform upon which it runs. Whether it is hardware or software, IT components have a lifespan. If you decided to look at other platforms to host the application, you should perform a detailed fit-for-purpose architectural analysis since porting from one platform to another rarely yields the intended results. Many applications have been written to optimally run on a specific platform, so you may find performance degraded with a straight port. Rewriting code is the last resort since it is the highest risk and most costly. Many modernization efforts to rewrite code have failed for lack of understanding the current systems and how the business logic works. Others have failed because of cost and schedule overruns due to underestimating the complexity. Getting the business logic right is critical but can be difficult since many of these applications were developed 15 or 20 years ago and the people who originally designed and wrote them are no longer in your organization. Reverse engineering the code is error-prone and quality problems can quickly sink your business. There are many tools on the market to help you understand your existing systems before you begin rewriting. Tools like IBM’s CICS Interdependency Analyzer can help you understand the complex relationships in your application so you can decide the best way to begin rewriting. But remember, you are introducing a lot of risk to your business when you do this. Challenges The biggest challenge to modernizing your enterprise is cost. Cost challenges come in many forms from the actual designing and writing of the system to testing and support. Costs can escalate because of down time and lost business if you prematurely put a modernized system into production. Your business can get a “black eye” in the industry if you experience too many outages. I have seen many more rewriting projects 2017: Issue 2 | E n t e r pr is e E xe cu t i ve | 53

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