How do you align software maintenance and evolution goals and strategies with business and customer needs?

1 Case Study 1: NASA's Space Shuttle Software

NASA's Space Shuttle Software (SSS) was one of the most complex and critical software systems ever developed, as it controlled the launch, orbit, landing, and emergency abort of the shuttle. The SSS evolved over three decades, from 1977 to 2011, through 27 releases and 2.5 million lines of code. The SSS maintenance and evolution process was driven by four main goals: safety, reliability, performance, and adaptability. To achieve these goals, NASA adopted a rigorous and disciplined approach, based on formal methods, verification and validation, configuration management, and continuous improvement. The SSS also had to cope with changing requirements, hardware upgrades, external dependencies, and legacy issues. NASA's SSS is an example of how software maintenance and evolution can ensure the success and longevity of a software system in a high-risk and dynamic environment.

2 Case Study 2: Google's Search Engine

Google's Search Engine (GSE) is one of the most popular and influential software products in the world, as it handles billions of queries per day and provides relevant and personalized results to users. The GSE evolved from a simple prototype in 1996 to a sophisticated and scalable system in 2021, through hundreds of updates and experiments. The GSE maintenance and evolution process was driven by two main goals: relevance and innovation. To achieve these goals, Google adopted a data-driven and user-centric approach, based on machine learning, experimentation, feedback, and iteration. The GSE also had to deal with diverse and dynamic data sources, user preferences, market trends, and competitors. Google's GSE is an example of how software maintenance and evolution can deliver value and differentiation to a software product in a competitive and evolving market.

3 Case Study 3: Netflix's Streaming Service

Netflix's Streaming Service (NSS) is one of the most popular and successful software platforms in the entertainment industry, as it provides millions of subscribers with access to thousands of movies and shows on demand. The NSS evolved from a DVD rental service in 1997 to a streaming service in 2007, through several transitions and transformations. The NSS maintenance and evolution process was driven by three main goals: quality, availability, and growth. To achieve these goals, Netflix adopted a cloud-based and microservices-oriented approach, based on resilience, scalability, and agility. The NSS also had to handle increasing and fluctuating demand, content diversity, device compatibility, and regulatory compliance. Netflix's NSS is an example of how software maintenance and evolution can enable the transition and transformation of a software platform in a disruptive and demanding industry.