Business Process Decomposition - The first step to modernizing legacy applications

When it comes to legacy applications, most often, we find that all the business processes/rules are hard-wired in business logic of legacy technologies like COBOL, Assembler etc. With the ever-changing technology landscape, it is necessary that these legacy applications must respond to new business requirements. Enabling responsiveness of legacy applications demands business rules modification and in turn, software alteration. These applications are therefore migrated and modernized to keep them at par with the changing technology landscape.

Business process decomposition and documentation is the very first step in a modernization exercise. Business process decomposition makes sure that the existing business processes embedded in legacy applications continue to remain on the target platform as these business rules/processes have enabled the business for a long time.

Broadly, we need business process decomposition and documentation for the following two pursuits:

Customer of the Shelf (COTS) product implementations: To help in gap analysis for customizing the enterprise COTS products according to the application functionality
Application rewrite: To help in rewriting the application to a new platform and to ensure replication of the current business process embedded in legacy applications on the new platform

Business process decomposition starts with collecting and baselining the existing inventory of functional and technical documentation available for the application. This helps in formulating a detailed understanding of the end-to-end application flow and aids the business process, technology mapping, and design and deployment architecture. This activity also provides an opportunity to identify any gaps in the available information and fill them through a detailed workshop with the identified stakeholders.

There are two approaches to business process decomposition:

Top Down approach or Functional Analysis:
- Collect relevant inventory of functional and technical documentation available for the application
- Create and share questionnaire to capture the details not available in the documentation i.e. identify any gaps in the available documentation
- Conduct workshop with stakeholders to fill the gaps in the documentation and identify various use cases which define the functionality of each applicatio
Bottom Up approach or Technical Analysis
- Collect all the application codebase covering common subroutines, application programs, database components and integration components
- Build application repository in the application analysis tool like Micro Focus Enterprise Analyzer (MF EA) with the inventory collected
- Generate various reports using MF EA to represent technical components implemented in each application
- Consolidate technical processes to represent functional modules identified in top-down analysis

A Hybrid approach, which is a combination of functional and technical analysis is used to understand and document the AS IS state of the application.

As part of the ‘Top Down’ approach, the documentation done during analysis phase is analyzed and any gaps in the information needed is noted, then a questionnaire is prepared and shared with stakeholders so that they are prepared for the workshop/meetings. Following this, ‘Bottom Up’ approach helps in understanding application functionality and identifying any discrepancy or gap in the available information. Code based analysis tools are used in understanding the application in more detail through application flows and the source code is parsed through the tool, which generates multiple reports such as CRUD, Call flow, Un-referred report, Cross Reference report etc.

The output at the end of the business process decomposition phase is a Functional Specification document, which captures the AS IS state of the application, thereby completing the first stage of migration.

Business process decomposition thus lays the foundation of the migration process and kick-starts legacy modernization.

About the Author

Vinod K. Boorugu, Principal Consultant, Business Application Services, Wipro Limited

Vinod has over 20 years of IT experience with over 6+ years of experience in Legacy/Mainframe modernization, having worked in areas like business process re-engineering, migration and decommissioning, among others. He has played a key role in helping many Fortune 500 companies modernize their legacy systems and make their IT systems digital-ready while preserving the organizational DNA.

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