Understanding Software Migration. part 1

28. May 2008 10:00 by lleon in General  //  Tags:   //   Comments (0)

Enterprise software is going beyond the line in matters of size and scalability; small companies depend on custom tailored software to manage their business rules, and large enterprises with onsite engineers, deal in a daily basis with the challenge to keep their systems up to date and running with the top edge technology.

In both cases the investment made in software systems to assist a given business is elevated, regardless if it was purchased from another company or if it was built and maintained by the own, it’s never going to stop being critical to update the current systems and platforms.

            Any enterprise software owner/designer/programmer must be aware of the market tendencies of operating systems, web technologies, hardware specs, and software patterns and brands; because of the raging nature of the IT industry it takes an eye blink to get obsolete.

Let’s recap about VB6 to VB.NET era, a transition with a lot of new technology, specs and a lot of new capabilities that promise the programmers to take their applications where it seems to be previously impossible like web services and remote facilities, numerous data providers are accessible with a common interface, and more wonders were presented with the .NET framework, however all this features can get very difficult or near to impossible to get incorporated in legacy applications. At this moment it was mandatory to get that software translated to the new architecture.

Initially the idea was to redesign the entire system using those new features in a natural way but this implicates to consume large amounts of resources and human efforts to recreate every single module, class, form, etc. This process results in a completely new application running over new technology that needs to be tested in the final environment, and that will impact the production performance because it has to be tested in the real business challenges. At the end, we got a new application attempting to copycat the behavior of the old programs and huge amount of resources spent.

Since this practice is exhaustive for the technical resources and for the production metrics, the computer scientists research about the functionally equivalent automated processes were used to create software that is capable to port one application from a given source platform to a different, and possibly upgraded one. During this translation process, the main objective is to use as much inherent constructions as possible in the newly generated code to take advantages of the target technology and to avoid the usage of legacy components. In case that the objective is to include a new feature found in the target platform, the application can be migrated and then the feature can be included more naturally than building communication subprograms to make that new capability to get in touch with the old technology.

This process is widely promising because it grants the creation of a new system based on the previous one, using minimum human efforts by establishing transformation rules to take the source constructions and generate equivalent constructions in the desired technology. Nevertheless, this will require human input, especially in very abstract constructions and user defined items.

All the comparisons done before to measure the benefits between redesign and migration, points to identify the second practice as the most cost-effective and fast, but now another metric becomes crucial. The automated stage is done by computers using proprietary technology depending on the vendor of the migration software, but how extensive the manual changes will be? Or, how hard will be to translate the non-migrated constructions?


The quality metrics of the final product will be redefined because a properly designed application will be translated with the same design considerations. This means that a given application will be migrated keeping the main aspects of design and the only changes in the resulting source code will be minor improvements in some language constructions and patterns. This makes the new quality metrics to be: maximize the automation ratio, minimize the amount of manual work needed, generate more maintainable code and reach the testing stage faster.