Software modernization

Legacy modernization, or software modernization, refers to the conversion, rewriting or porting of a legacy system to a modern computer programming language, software libraries, protocols, or hardware platform. Legacy transformation aims to retain and extend the value of the legacy investment through migration to new platforms.

Legacy system modernization is often a large, multi-year project. Because these legacy systems are often critical in the operations of most enterprises, deploying the modernized system all at once introduces an unacceptable level of operational risk. As a result, legacy systems are typically modernized incrementally. Initially, the system consists completely of legacy code. As each increment is completed, the percentage of legacy code decreases. Eventually, the system is completely modernized. A migration strategy must ensure that the system remains fully functional during the modernization effort.

Making of software modernization decisions is a process within some organizational context. “Real world” decision making in business organizations often has to be made based on “bounded rationality”. Besides that, there exist multiple (and possibly conflicting) decision criteria; the certainty, completeness, and availability of useful information (as a basis for the decision) is often limited.

Primary issues with a legacy system include very old systems with lack of documentation, lack of SMEs/ knowledge on the legacy systems and dearth of technology skills in which the legacy systems have been implemented. Typical legacy systems have been in existence for more than two decades. Migrating is fraught with challenges:

Last but not the least, there is no one stop solution-fits all kind of option in modernization. With a multitude of commercial and bespoke options available for modernization, it’s critical for the customers, the sellers and the executors to understand the intricacies of various modernization techniques, their best applicable implementations, suitability in a particular context, and the best practices to follow before selecting the right modernization approach.

Over the years, several different options have come into being for legacy modernization – each of them met with varying success and adoption. Even now, there is a range of possibilities, as explained below, and there is no “the option” for all legacy transformation initiatives.

A legacy code is any application based on older technologies and hardware, such as mainframes, that continues to provide core services to an organization. Legacy applications are frequently large and difficult to modify, and scrapping or replacing them often means re-engineering an organization’s business processes as well. However, more and more applications that were written in so called modern languages like java are becoming legacy. Whereas 'legacy' languages such as COBOL are top on the list for what would be considered legacy, software written in newer languages can be just as monolithic, hard to modify, and thus, be candidates of modernization projects.

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