Getting to performance - implementing an application redevelopment strategy in MIS - Forum: Open Files - Column

Software Magazine, Sept, 1992 by Charlotte Hart Riordan

Many IS organizations have begun redeveloping their legacy application suites. Hoping to eliminate business problems caused by undocumented, unstructured code, these firms are trying to deploy new applications that can be adapted quickly to changing business requirements. The goal is to replace third-generation spaghetti code with clean, computer-aided software engineering (Case)-based programs that are less costly to maintain.

Implementing a redevelopment strategy includes selecting multistage methodologies, evaluating and purchasing supporting tools, training Staff and expanding substantial management time. While a significant challenge, it is an opportunity for developers to deliver quality applications with improved maintainability, usability, portability, reusability, dependability and availability. However, only when application performance is targeted for improvement can the opportunity be fully realized.

Application programmers and system programmers play a vital role during any redevelopment effort. Application programmers are charged with the task of restructuring, reengineering and adding new functions to complex business applications. System programmers must deliver resources to legacy and redeployed applications, while maintaining service-level commitments and avoiding costly hardware upgrades.

While system programmers can achieve success in suppressing system and subsystem appetites for resources in today's rapidly changing environment, who is watching the diet of the applications?

NEW DISCIPLINE OF APM

Maybe no one. IS organizations have neglected the accountability for built-in application efficiency and the responsibility for managing lifetime application performance. Sharp IS managers may recognize the problem and its cost-related implications for corporate IS, but because the term application performance management (APM) has yet to become standard IS vocabulary, many may be unaware of the solution.

Establishing this new IS discipline requires defining practices, supplying tools to support those practices and defining the interaction between technique and technology.

APM provides the framework and tools to manage an applications resource consumption and responsiveness throughout its life cycle. APM tools enable the practitioner to:

* Measure an applications performance to create benchmarks and standards;

* Identify resources consumed by an application- whether in user code or in system code;

* Pinpoint specific application code blocks on which performance improvement efforts can be focused;

* Measure, evaluate, analyze and eliminate application inefficiencies;

* Implement ongoing control and reporting procedures for improvement of application performance.

With APM practices, programmers can address application performance at every stage in the redevelopment cycle. This lets programmers build in quality attributes -- efficiency and responsiveness -- and reduce the lifetime costs of the application by minimizing resource demands.

In the initial analysis phase of the redevelopment effort, an APM practitioner tunes applications in the legacy environment to create best-case benchmarks. This practice generates essential metrics for efficiency and responsiveness that are then added to other traditional application quality and complexity metrics.

These metrics help identify candidates for redevelopment. Through the subsequent phases of a redevelopment project, continuing APM practices ensure that redeveloped applications meet or exceed standards established in the initial performance benchmarks.

With easy-to-use APM tools, application programmers can judge the performance impact of their design decisions, compare the efficiency of code produced by different development tools and create libraries of efficient reusable code blocks.

APM also ensures that IS shops can preserve their immense investment in redevelopment. The IS technical and business environments are rapidly changing. By embracing APM practices, IS organizations can prevent applications from taking on the inferior characteristics of their ancestors. Application quality can then be maintained and improved over time.