When Tech ‘Upgrades’ Go Awry

Microsoft’s Outlook and related cloud services failed for millions of users, while a fault in the FAA’s ageing data equipment led it to ground all flights in the United States. Both disruptions followed attempted upgrades, showing how changes intended to improve complex systems can instead interrupt services that businesses and the public rely on.

Microsoft restored its services on Saturday, and the FAA lifted its grounding order on Friday night, though hundreds of thousands of passengers were stranded over the weekend. The article says major systems are built up in layers over many years: COBOL, created in 1959 as a temporary business programming language, still runs financial systems that process more than $1 trillion in transactions daily. Experts attribute such risks partly to software development that prizes speed and features, and some companies are using detailed simulations to find faults before systems go live.