Transposition - the success story of VB6 migration

Since all of you VB developers in the present or past would probably find it hard to believe that the old VB code can be migrated and modernized into the latest .NET based HTML5 without having to rewrite the application I am feeling I need to write another post on our migration solution. Hopefully, after reading this and the previous post you will be able to understand the different approach of our solution which already helps organizations around the world move away from the constraints of VB6 and free them to access the applications from any computer or browser-supported devices. I will write on such organization later in this post.

As discussed before the solution is called Instant CloudMove while its main tool is called the Transposition Studio. Why transposition you probably ask yourself?! Well, we found that this term best describes what the tools do. Transposition refers to exchanging elements while everything else remains the same (in mathematics) or moving an element as is from one environment to another (in music). So how dows this relate to software and programming? Well, due to the award-winning Visual WebGui platform we are able to take the source code and put it in a modern technological environment with relatively few adjustments. As you can see in the diagram below Visual WebGui preserved the server centric architecture of client/server applications - enabling the same methodology of work by optimizing the message queue over the web:

Visual WebGui Architecture

So as you can see we have a better starting point to get the code run over the web. But what about the migration process itself?

Here we also bring a refreshing approach that is based on a set of Mapping Expressions which are basically links between an element in the source environment and one in the target environment that has the same functionality. About 95% of the code is usually mapped out-of-the-box and the rest is handled with easy-to-use mapping tools designed for Visual Studio developers providing them with a familiar environment and concepts for completing the mapping and allowing them to extend and customize existing mapping expressions. The solution is also based on a circular workflow that enables developers to make any changes as required until the result is satisfying.

As opposed to existing migration solutions that offer automation are usually a “black box” to the user, the transposition concept enables full visibility, flexibility and control over the code and process at all times allowing to also add/change functionalities or upgrade the UI within the process and tools.

This is exactly the case with our customer’s aging VB6 PMS (Property Management System) which needed a technological update as well as a design refresh. The decision was to move the VB6 application which had about 1 million lines of code into the latest web technology. Since the application was initially written 13 years ago and had many upgrades since the code must be very patchy and includes unused sections. As a result, the company Mihshuv Group considered rewriting the entire application in Java since it already had the knowledge. Rewrite would allow starting with a clean slate and designing functionality, database architecture, UI without any constraints. On the other hand, rewrite entitles a long and detailed specification work as well as a thorough QA and this translates into a long project with high risk and costs.

So the company looked for a migration solution as an alternative; the research lead to Gizmox and after examining the technology it was decided to perform a hybrid project which would include an automatic transposition of the core of the VB6 application (200,000 lines of code) while they redesigning the UI, adding new functionality, deleting unused code and rewriting about 140 reports with Crystal Reports will be done manually using Visual WebGui development tools.

The migration part of the project was completed in 65 days by 3 developers from Mihshuv Group guided by Gizmox migration experts while the rewrite and UI upgrade tasks took about the same. So in only a few months period Mihshuv Group generated an up-to-date product, written in the latest Web technology with modern, friendly UI and improved functionality.

Guest selection screen of the original VB6 PMS
Guest selection screen of the original VB6 PMS

Guest selection screen on the new web–based PMS
Guest selection screen on the new web–based PMS

Compared to the initial plan to rewrite the entire application in Java, the hybrid migration/rewrite approach taken by Mihshuv Group using Gizmox technology proved as a great decision. In terms of time and cost there were substantial savings; from a project that was priced for at least a year (without taking into account the huge risk and uncertainty) it became a few months project only.

More about this and other customer stories can be found here

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