As any CIO/CTO will tell you legacy transformation is here to say. What is the definition of legacy? A prompt answer would be – something that is old. But Legacy transformation is not about doing away with old and switching to a new one at a throw of a switch. It is something that needs to be thought through. Some of the main challenges are:
- Phasing out the old system
If the organization decides to retire the old application because a new one would take its place, the old system has to be phased out. All old linkages, pre-dependent and post-dependent application would have cut and sutured as it were to manage the removal. Sunset dates for old data formats and new ones have to be managed for seamless transition
- Coexisting with old system
Often it is not possible in the short run to phase out the old system but to actually co-exist with it instead. The challenges here are to effectively partition the functionality between the old and the new systems around the same. Scaffolding for new data interfaces needs to be built. Usually most organizations web-enable their old application to cater to new client devices or offer new web based functionality. Some banks and insurance companies have done this very efficiently
- Migration and transformation
Some organizations attempt migration of old systems to new one and in this process they would explore transformation approaches, for example from PL/1 to say C++. The challenges here would be to understand that transformation usually can deliver – in this example – a PL/1 application that can run under C++. No architectural or inherent advantages of C++ environment are possible. Additional effort needs to be cpent in making it C++ perfect and that means delayed deployment.
- Absence of skill sets
Perhaps the most deterrent of the challenges to transformation is the unavailability or very limited availability of skill sets around the older technologies. This leads to retro-documentation efforts of older systems because all documentations are either obsolete or simply not available.
- Assessing the legacy systems foot print
Whatever be the decision going forward a big challenge is to assess the system itself. How much the code is active? What parts of the inventory are used or obsolete? Over years the application accumulates unwanted code snippets and version that simply bloat the application and very few people have an idea of what is useful and active.
I am sure there are more, but these are the important ones that drive many of the CIO/CTOs up the wall.