IS modernization process vs target architecture

Question is: in an ADM automated process, has the target architecture definition to be part of the process? Or has it to be (pre)defined regarding enterprise architectural IT plan?

Answer is: both but enterprise business needs rank first.

In an ADM process, a transformation path has to be found from the source code to the target code, and so from the source logical architecture to the target logical architecture. First point, if no path may be found the ADM process is not suitable! If paths exist, they can be very light or very tough, or more likely between these extremes. The key point will be: how much does it costs to build the transformation set of rules? And how much work will remain to be done outside the transformation? Considering this cost aspect is the only reason to interfere with the target architecture definition: the ADM process’ mission is to bring an application from one implementation technology point to another point… Not to choose the destination!

From the business needs side, it is highly expected that a target architecture has been defined before launching the modernization project. Either the initial need is to bring the application to be modernized into an existing architectural environment, either a cost savings move leads to quit the current technology. The first case is trivial, and in the second case the target architecture choice is guided by costs consideration and IT modernization matters (mainly availability of competent human resources).

So, the target architecture has mainly to be defined outside the ADM process but may be refined for modernization project costs saving purpose. However, even if refined, the target architecture has still to be highly compliant with the mainstream enterprise architecture otherwise the result will be to increase maintenance costs, which in long-term will cost much more than the savings obtained immediately at the end of the modernization project…