Rethinking Legacy Systems

 

"Legacy applications are a goldmine of valuable business rules and design intelligence."

 

"Modern developers want nothing to do with RPG or the AS/400 other than get rid of them."

 

You've probably heard these seemingly conflicting statements.

 

My theory is this:

 

So is it possible to manage a legacy system in a modern way?

 

Business Processes, Business Rules, Business Data

Gee, you would think it's all about the business!

 

Well, it is, of course, and new tools and methodologies reflect that. IBM's own leading tools focus first on Business Process Management (BPM) and then WebSphere Lombardi for implementation; they also use iLog as a Business Rule Management System (BRMS).

 

There are big benefits to defining systems in a language closer to business terms, rather than in programming terms. Less translation means faster development, fewer errors, truer modeling, better comprehension, and improved communication.

 

That's great for new development, but what about legacy applications?

 

Advanced Paradigms for Legacy Systems?

While most legacy IT people think of their systems in terms of objects and lines of code, there's the opportunity to automatically translate much of the system back to being closer to business terms.

 

Here's the important point:

 

(For a deeper look at using business rules in legacy systems, see the Visual Guide to Business Rule Reuse.)

 

Most of the business rules and data model rules in your current system will also be found someday in the successor system. Here's the concept illustrated:

 

Figure 1: Business and data rules stay with the system.

 

The IT Trustee

As managers of software applications, IT managers are trustees of these business rules and data model rules. These are the things that businesses truly care about. How many IT managers of legacy applications can list their business rules? Or confirm that they're accurate? And consistent?

 

Because of the way programming has evolved, legacy applications are managed in a programming-centric manner, rather than business-centric.

 

But that's not the future. Nor should it be the present if there is any hope of realizing the gains available from BPM and BRMSes.

 

It's the business-centric view that leads to a logical, informed strategy about future system directions.

 

Prepare for Tomorrow's System by Improving Today's System

That heading sounds like a noble thought that never quite goes anywhere.You have to make it go somewhere.

 

If you've understood the essence of this discussion, then you've understood that:

 

The business rules you're managing today are the business rules you'll be managing tomorrow, whether they're in your current application or its successor. They will evolve, to be sure, but mostly they are the same.

 

"What gets managed gets improved."

—Bill Hewlett, founder Hewlett-Packard

 

Here's the question for managers of legacy applications in RPG, COBOL, or CA:2E:

 

Manage a Legacy System in a Modern Way

This may sound wonderful but impossible. But it can in fact be done by using an advanced paradigm product that enables recovery and reuse of application design elements, such as business rules, data model rules, and business processes:static analysis and design recovery tools.

 

For 25 years, Databorough has been building and deploying increasingly advanced versions of the X-Analysis tool suite to extract, analyze, and reuse information from legacy RPG and COBOL applications. In recent years, the product has evolved to where it specifically extracts business rules, data model rules, and business process information, thereby enabling a move to a modern business-centric approach and even assisting in automatically rebuilding these designs with modern technologies and methods.

 

Time to Rethink

By adopting a more business-centric system perspective, you begin to chart a more productive path to the future, whether it's to improve your current IT processes or lead the way to new systems.

 

Leading legacy organizations are leaving the old programming-centric view of objects and lines of code and moving to a business-centric view of business rules, data model rules, and business processes, and charting a logical, informed course to the future.