Why is Legacy Software Maintenance so difficult to manage?

Many managers have a problem managing legacy software systems and this article will discuss some of the reasons for that. Almost every company that has been using computers for any length of time has developed some in-house software that meets a very specific need that cannot be met by COTs packages. Anytime you deploy a software system into production, it becomes a legacy system by definition, and for good or bad it becomes part of the company’s portfolio. Some of these systems become very successful and enjoy a long deployment cycle.

Almost immediately after the new system was deployed, however, the most skilled developers on the project leave to develop on other projects or find bigger challenges with other companies. Unless the system design was well documented, most of the knowledge of the application left at that point. As the application entered maintenance mode, fewer and fewer developers who knew the design of the original system remained. Over time, the application evolved from its original version usually in response to business and technology needs, and it continued to provide a greater value for the company. These are the kind of applications which companies decided to keep.

Eventually, the application begins to show signs of age and the technology upon which it was based becomes obsolete and incapable of supporting the new business requirements. Patching the code for new features is no longer a viable alternative. Your legacy application has evolved to a certain point, but now the changes needed exceed the constraints of its design and it has become brittle and resistant to further change. This is a normal evolutionary process and something that every organization has to respond to.

Unfortunately, as your application has evolved, the skills of the developers that maintain it haven’t always kept up with the latest technology. With more and more new features being provided by open source, third party software and new technology, managers find themselves looking for outside help to bridge the technology skills gap. They run into problems fitting these developers into their legacy environment because of a mismatch of skills. Newer developers usually lack the background in legacy systems required to understand the design of the application and there are very few places they can pick this knowledge up. The older developers who have been maintaining the old system often don’t investigate the new technology since it is not a part of their job description.

Along with the maturation of the application, the company’s perception of the importance of the developer is reduced, so the resources to keep these skills are also reduced. Pretty soon the expertise needed for legacy development has evaporated and the knowledge of the history of the application is reduced to one or two maintenance programmers. Their strength lies in the understanding of the history of the application and not necessarily in the inherent design. The design knowledge is gone but the need for redesign will require this same type of skill (usually a mismatch with the skill set of the remaining developers). In order to extend the design of your legacy system, you need the skills of a highly skilled developer and to attract this type of developer, you will need to have a modern environment for them to develop in.

This is the problem many companies with legacy systems face: the business logic that legacy systems perform and value to the company needs to be retained and extended because the cost of any other option (i.e. a re-write) is too risky and cost prohibitive. Many CIOs have faced this problem and have analyzed and assessed their inherited legacy systems only to defer any changes due to the risk. That risk is now becoming greater with the passage of time as the technology gap widens and the expertise that is currently maintaining the legacy system is getting close to retirement age. The talent pool of legacy developers is shrinking every year and it is not being replenished with college graduates who are willing to learn this old technology.

While newer technology can replace much of the functionality of legacy systems, the business logic which it performs cannot be replaced. So the problem you have is finding the right mix of developers and technology tools to implement a new design through integration. What is the best way to achieve this goal? Perhaps there is a solution already out there – check out this video:



Leave a Reply