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Technology: Migration – Legacy Systems To 4GL Technology - Part II


Migration – Legacy Systems to 4GL Technology

Legacy applications are frequently large, monolithic and difficult to modify, and scrapping or replacing them often means reengineering an organization’s business processes (workflow) as well. Legacy migration is about retaining and extending the value of the legacy investment through migration to new platforms. This article discusses the benefits and migration tools for migrating from leagacy systems to 4GL technology.

The following Enterprise Architecture gives the flexibility and scalability to the current and future business need. Any type of clients can interact with the common system to form a single transparent enterprise online.


Existing systems were optimized to perform functionality in a predefined structure. The business today in the global market calls for frequent change in functionality implementation that demands fresh development efforts to expand the capabilities of the existing system. The consequences of which are time & costs and handicaps in coping up with the new functionality requirements.

Existing systems are usually tied to an existing vendor offering and are hence proprietary. The business’s need today is to be able to communicate seamlessly to many systems and be open to other application systems.

The migrated Business Component will be deployed as a CORBA object in the application server, which can be accessed by any front end applications written in any languages like Visual Basic, Java etc.

Any additional developments can be done using Java and EJB’s, and can be deployed in the same server. There fore both the components can co-exist in the same application server, commonly accessing the business logic, which is in true sense an open architecture

Migrate Using Power Migrator™ tool
This option of migrating the application to the web using our Power Migrator™ tool is discussed now.

As discussed earlier, most organizations and users are fearful of the fact of moving the client server application to the web for many reasons. The costs are prohibitive, the learning curves are very high and the users are not sure if the migrated application’s look and feel is similar to that of the original application.

Now we discuss how the apprehensions can be resolved using Power Migrator™  

As we are using the same code for migration, there is no need to learn new skills
The existing development team’s Power Builder Skills are sufficient enough to work with Power Migrator™ to move the application to the web.
A few junior level JSP programmers may be required, in case the generated JSP code needs to be altered.

Reusability of the existing Code
The most compelling reason would be that it allows the client to leverage the existing Power Builder code and use that to move the applications quickly. If the client application is a large application, it would make sense to assume that lots of business logic has gone into the code. This could be missed in the event of a rewrite.

If the application is fairly large, that have been evolving over time, it would make sense to use the skills sets of the present development staff, and into which investments of thousands of dollars would have gone into. These costs can be completely saved, as there are no training costs.

Cost benefits
The cost benefits are enormous for the reasons so far discussed. The path towards migrating the current application would take less than half the time it takes to rewrite the entire software. Similar cost benefits are indicated, taking into account the huge infrastructure investments to be made for rewriting the application. The effort to migrate the application is also lesser considering the fact that the application is already put in use and the development staff are skilled on the application.

Learning Curves.
Negligible learning costs, as the Power Migrator™ is an automated tool.

Component coexistence
After migrating the application to the web, instances may occur that fresh developments may need to be done to either the same application or a completely new development can be started using Java and EJB’s. In such cases the components can co –exist on the same application server without encountering any technical problems. No need to invest on a new application server.

(Vidya received her MA in Communications from Madras University. She started SolveIT in 2003 to develop the tool to support migration. She can be reached at vidya@solveitcorp.com. )

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