Great Migrations Methodology
The Agile Rewrite
Great Migrations' Tool-Assisted Rewrite Methodology is designed to migrate VB6/ASP applications to .NET and do so in a way that is "agile": producing valuable results very quickly and facilitating predictable, incremental quality improvement through an iterative process we call "translation tuning".
Each iteration has the following steps: Preparation, Translation, and Verification .
Preparation means capturing your upgrade project requirements in the tool's configuration. At a minimum this is defining three things:
- The location of the legacy code that you want to upgrade
- The .NET language to which you want to upgrade (C# or VB.NET) -- our default is C#.
- The version of .NET framework and IDE you want to use -- our default is .NET 3.5 and VS2008.
Translation (a.k.a. Migration, a.k.a. Tool-Assisted Re-Writing) means using the tool to produce an upgraded version of the legacy code that is written in a chosen language and compatible with the target platform.
Verification means determining how well the translation meets your requirements and deciding if you should do another iteration by tool or finish the task by hand.
The above steps are repeated several times, each time refining the design of the target application and the conversion process. The process of moving from the proverbial "first translation" into iterative "translation tuning" is a smooth one as the initial preparation work sets up your migration workspace and produces the baseline scripts that you can then refine in subsequent tuning cycles.
Cut-Over means doing your final translation of the source codebase. When the team agrees that the conversion process is "good enough" and the only issues left are those that were identified as being easier to do by hand, they do a final translation. This is followed by a short Fit & Finish phase to certify the new system and deploy it to production.