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Modernizing Legacy iSeries Systems

Leverage, evolution, and flexibility are key

IBM iSeries systems are installed in an estimated 250,000 organizations. If yours is one of them, then most likely your group is either interested in or committed to modernization, which could mean you wish to enhance the user interface while maintaining the existing core business logic, or to integrate data on an AS/400 with Windows-centric, SQL-based back-office applications, or to implement a service-oriented architecture (SOA) and offer Web services to better serve your customers and your enterprise's own competitiveness.

Whatever the level of modernization you are currently seeking, the existence of the iSeries presents both challenges and opportunities. The challenge is to determine the best way to bring the enterprise system into the 21st century without incurring unnecessary disruption to the business, while managing costs and achieving a reasonable timeline. The opportunity is to leverage the valuable asset that is the iSeries itself - including its reliability, performance, ease of use, and familiarity - along with the associated assets in existing data, developer-born applications, and staff expertise.

The options for modernization are many. To evaluate and select among the possibilities, an articulated set of goals and an awareness of the assets to be leveraged and preserved will be valuable. These goals and assets are interrelated, in the sense that among your goals, it is important to consider the ability to maximize iSeries assets. You may consider these assets in terms of the literal building blocks of the system: RPG programs, CL programs, DDS display, print files, data files, and so forth. For a more enterprise-wide perspective, however, also consider your assets in terms of the "four pillars" of an organization's IT "ecosystem." These are:

  1. The people (your existing programming staff, including RPG programmers, C# people, VB folks, and so forth, as well as anyone else who interacts with, is affected by, or has expertise in the system AND the company's business)
  2. The applications (which represent the sum total of your company's IT existence, and are often complex and comprehensive - but whose value erodes when they are not readily extended to other applications, interfaces, and Web services)
  3. The processes (which depend on IT technologies for support, and benefit from leaner, integrated methodologies - but these require change and adaptation throughout the organization)
  4. The data (both on the iSeries and on Windows-based or any other system you may already have)
Each of these categories of asset is important not only to the iSeries system but to the organization as a whole. Each represents an investment that can be either lost, preserved, or enhanced through the modernization initiative. All four merit careful consideration as to the way they may be impacted by, respond to, or contribute to the changes you are considering.

With this insight into your organization, your goals, and your assets, you can begin to consider the modernization options, ideally without becoming mired in the plethora of possibilities.

Java/WebSphere or .NET?
Although this oversimplifies the situation, the looming question at the outset is whether to proceed with a Java/WebSphere solution or to consider an alternative - that is to say, .NET - for your Web/SOA realm. IBM's original iSeries Developer Roadmap was certainly intended to steer iSeries shops toward a Java-centric future. The disadvantages to this route, however, have proven so great that even IBM has backed off from its insistence on Java/WebSphere and begun to recognize a role for third-party solutions.

For large enterprises that can bear the risk and costs of Java projects, the Java/WebSphere route may make sense. For small and midrange companies (which make up the majority of OS/400 shops), budget, staff, and time considerations require them to be more circumspect. They must consider alternatives that decrease the risks and costs of switching to an unfamiliar language, retraining or hiring new programmers, and rewriting reams of code.

Microsoft's .NET platform has emerged as an alternative modernization path for iSeries shops that are looking for a faster, less expensive, and less cumbersome route. Adoption of .NET is particularly of interest to companies that are implementing Web services and SOA. In addition, because it embraces many programming languages, it provides flexibility and advantages in terms of cost and staff considerations - developers can use whatever language is most appropriate for them and the project.

The Options
Although Java/WebSphere and .NET are the routes of choice for many enterprises that are undertaking modernization of iSeries systems, these are not the only alternatives. All of the following are means by which an organization can achieve a degree of modernization (or at least the veneer of it):

  • Replace or rewrite applications
  • RPG/400 emulation
  • RPG/400 screen scrape
  • Host-based ad hoc
  • Migration to Java/C#
  • RPG portfolio transformation
In reality, these options are not mutually exclusive. An organization will choose the path that is best for the job and for the enterprise, and sometimes that means a combination of alternatives. This may mean the use of DB2/400 databases, SQL databases, Windows Servers, and IBM iSeries eServers in any combination according to requirements and goals.

More Stories By Mike Marlowe

Mike Marlowe leads the pre-sales team at ASNA as a pre-sales engineer andWindows and Web development trainer specializing in both .NET- and COM-based technologies. Mike is instrumental in educating prospects on ASNA's technology message as well as assisting with conceptual applicationplanning and development. Mike also assists with developing and deployingASNA's training curriculum.

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