What are the challenges of evaluating software architecture in a legacy system?

1 Challenge 1: Lack of documentation

One of the most common challenges of evaluating software architecture in a legacy system is the lack of documentation. Documentation is essential for understanding the rationale, decisions, and trade-offs behind the architectural design. Without documentation, it can be hard to identify the architectural elements, their responsibilities, and their dependencies. Moreover, documentation can become outdated or inconsistent with the actual implementation over time, leading to confusion and errors.

To overcome this challenge, you need to use various sources of information to reconstruct the architectural view of the legacy system. These sources can include code analysis tools, reverse engineering techniques, interviews with developers and stakeholders, and historical records. You also need to validate and update the documentation as you perform the evaluation, and document any assumptions or limitations that you encounter.

2 Challenge 2: Complexity and heterogeneity

Another challenge of evaluating software architecture in a legacy system is the complexity and heterogeneity of the system. Legacy systems often have a large code base, multiple layers, and diverse technologies. They may also have evolved over time, resulting in architectural erosion, degradation, or drift. These factors can make it difficult to understand the structure, behavior, and quality of the system, and to apply consistent and coherent evaluation methods and criteria.

To overcome this challenge, you need to adopt a systematic and modular approach to evaluating software architecture in a legacy system. You need to define the scope and objectives of the evaluation, and select the appropriate evaluation techniques and metrics. You also need to decompose the system into manageable and meaningful architectural components, and evaluate them individually and collectively. You may also need to use different evaluation methods for different parts of the system, depending on their characteristics and requirements.

3 Challenge 3: Stakeholder involvement

A third challenge of evaluating software architecture in a legacy system is the stakeholder involvement. Stakeholders are the people who have an interest or influence on the system, such as users, customers, managers, developers, testers, and maintainers. Stakeholder involvement is important for defining the evaluation goals, criteria, and scenarios, and for providing feedback and validation on the evaluation results. However, involving stakeholders in the evaluation of a legacy system can be challenging, due to factors such as availability, communication, expectations, and resistance.

To overcome this challenge, you need to establish and maintain effective communication and collaboration with the stakeholders throughout the evaluation process. You need to identify and engage the relevant stakeholders, and clarify their roles and responsibilities. You also need to communicate the purpose, scope, and outcomes of the evaluation, and solicit their input and opinions. You need to manage their expectations and address their concerns, and present the evaluation results in a clear and actionable way.

4 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?