• Abhishek Verma, Manager |
5 min read

Unlocking the future of legacy systems: An in-depth exploration of Mainframe Modernisation and its pivotal role in driving business innovation, reducing costs, and enhancing agility in the ever-evolving digital ecosystem

In an era dominated by disruptive technology, one might wonder about the relevance of mainframe computers. However, far from being obsolete, these robust and reliable systems are deeply entrenched in numerous industries. They power crucial business operations, ranging from financial transactions to airline reservations. The challenge now lies in modernising these mainframe systems to match the dynamism of today's digital environment. Mainframe modernisation, therefore, is not a luxury, but a necessity.

Mainframe Modernisation: A necessity, not a luxury

The concept of mainframe modernisation revolves around upgrading and optimising these systems to interact more fluidly with contemporary technologies. It aims to enhance the mainframe's agility, reduce operating costs, and most importantly, sustain its relevance in the face of fast-paced technological evolution. While the modernisation process can be complex, the rewards significantly outweigh the challenges, making it a compelling choice for businesses worldwide.


There are two paths in the mainframe modernisation process – Strategy and Technology – and these are intertwined, each playing a vital role in a successful mainframe modernisation project.

The Strategy Path focuses on the bigger picture, aiming to align the modernisation efforts with the organisation's broader business goals and risk appetite. It begins with a comprehensive evaluation and risk analysis to understand the current mainframe environment and potential modernisation challenges. Based on this understanding, a tailored modernisation strategy is developed to guide the project. Once the strategy is implemented, integration testing ensures the modernised system interacts effectively with other systems and meets business requirements. The final stage is continuous monitoring and performance optimisation, ensuring the system is running at peak efficiency and identifying areas for future improvement.

The Technology Path, on the other hand, is more concerned with the specific technical aspects of the modernisation process. It starts with identifying the applications that need modernisation and then choosing the most suitable modernisation approach (rehosting, refactoring, retiring, rebuilding, replacing, or encapsulation). The implementation stage is where the chosen approach is applied to modernise the mainframe. Post-modernisation management involves overseeing the new system to ensure it functions as intended and contributes to business objectives.    

In essence, the Strategy and Technology paths represent the two crucial facets of mainframe modernisation – planning and execution. While the Technology path handles the "how" of modernisation, the Strategy path addresses the "why" and "what" aspects. They need to work in harmony for successful mainframe modernisation. The strategic insights inform the technological decisions, ensuring the modernisation aligns with business objectives, while the technical implementation brings the strategic plan to life, translating the organisation's modernisation vision into reality.

Migration strategies and tools

  1. Rehosting: This approach involves migrating existing applications to a new platform without changing the underlying business logic. It is cost-effective and reduces the dependency on the ageing mainframe technology.
  2. Refactoring: Refactoring involves re-architecting and re-coding applications to be more compatible with modern platforms. It is a labour-intensive process but offers benefits in terms of scalability, flexibility, and the ability to integrate with new technologies.
  3. Retiring: In some cases, certain applications or components may be outdated or redundant and could be phased out entirely.
  4. Rebuilding and Replacing: Sometimes, the best solution is to rebuild the system from scratch or replace it with a modern, off-the-shelf solution.
  5. Encapsulation: This involves integrating the mainframe with modern applications and platforms via APIs, keeping the core mainframe system intact.

The choice of migration strategy depends on factors such as budget, timeline, complexity, desired level of modernisation, and business goals. It is essential to conduct a thorough assessment of the mainframe application, its dependencies, and the desired outcomes of the migration project before selecting the most appropriate strategy.

Moving a mainframes application to public cloud, such as Microsoft Azure, is enabled by various migration tools supported by Cloud Server Providers and third parties. Micro Focus Enterprise Server is one commonly used tool that provides a complete mainframe application rehosting solution, allowing migration of COBOL, PL/I, and Assembler applications to Azure. It includes features for code analysis, conversion, testing, and ongoing maintenance. Other similar tools are Modern Systems, TmaxSoft OpenFrame, which offers automated code and data conversion, as well as compatibility with various databases and middleware. Tools like Astadia help rehost mainframe applications to public cloud by automatically converting COBOL, JCL, and data structures into modern languages like C#, Java, or .NET.

Key factors to consider during Mainframe Modernisation

Risk Mitigation: Undertaking any modernisation process inherently involves risks. To mitigate these, organisations must carefully evaluate their mainframe architecture, understand the interdependencies, and prepare a comprehensive modernisation roadmap.

Skills and Expertise: Mainframe systems are complex. Modernising them requires a deep understanding of the technology and skilled professionals who can effectively carry out the process.

Investment: While the initial cost of modernisation can be significant, the long-term benefits in terms of operational efficiency, agility, and innovation drive a high return on investment.

The path towards mainframe modernisation is laden with complexities and challenges, yet it promises immense potential for businesses willing to undertake this transformative journey. As we stand on the cusp of an exciting digital future, the mainframe continues to play a critical role in the enterprise landscape. Its modernisation isn't just about surviving but thriving in a digital-first world. The key lies in adopting a balanced and thoughtful approach, blending the traditional mainframe strengths with the innovative spirit of the digital age.