Practically every information technology professional has encountered a legacy IT system at some point in their career. They come in a myriad of forms, often a combination of software written long ago running on operating systems that are well past their end-of-life, sometimes powered by years-old hardware kept running with used parts that are no longer being manufactured.
These systems are frequently too deeply ingrained into operations to permit downtime, too complex to upgrade or replace, and yet too business-critical to fail. When combined with management more willing to kick the can down the road rather than undertake the colossal task of bringing them up to date—or accept the risk of a failed attempt to do so—legacy IT system failures can be disastrous.
While such incidents are often widely publicized affairs impacting hundreds of thousands of customers across a large geographical area, legacy IT systems are not limited to national banks, government offices, or global corporate behemoths. Such systems often power the daily operations of even modestly sized companies, quietly going about their work...until they don’t, leaving stakeholders scrambling to recover from the impact. There are competitive consequences as well: startup companies working with ‘from scratch’ IT systems can often move faster to capture customers from businesses languishing in years of technological debt.
Even if outdated, irreplaceable hardware never fails or unpatched operating systems or software aren’t exploited by a malicious hacker, the expenses of keeping legacy systems running can consume a substantial portion of IT budgets, leaving little room for modernization and even less time to plan for it. Since 2010, an estimated $2.5 trillion of global spending was directed toward attempting to replace legacy IT systems, with at least $720 billion expended on efforts that ultimately failed. As businesses continue to implement new technology, IT departments can find themselves devoting a significant amount of time adapting the new to the old, resulting in additional layers of complexity and further points of potential failure.
While there is no simple or easy solution to the problem of legacy IT systems, businesses can still position themselves for success by ensuring adequate resources are devoted to maintaining and modernizing IT systems. Adopting development models geared toward continual improvement, testing, and deployment may also drive positive change, and help keep critical IT systems from ever becoming ‘legacy’ to begin with.