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What to Know About Y2K, Before You Watch 'Y2K'

The Year 2000 computer problem continues to nag at us 25 years later.

Reflecting on the actual Y2K is a reminder that computing’s real risks have less to do with murderous robots—and far more to do with how reliant we are on poorly maintained lines of code.

Indeed, that’s what made Y2K so novel. The harbinger of doom was not an ancient prophecy or a vast government conspiracy, but rather a straightforward issue with computers. Thus, even amid reassurances from the experts working on Y2K that the problem was being handled, Y2K forced people to acknowledge how dependent they were on oft-unseen computer systems. Ultimately, Y2K was less about the fear that the sky is falling, and more about the recognition that computer systems were holding up the sky.

Y2K emerged out of a basic computing problem: in order to save memory, computer professionals truncated dates by lopping off the century digits: turning 1950 into 50. Wondering how this might become a problem? Consider the following: 1999 minus 1950 equals 49, 99 minus 50 also equals 49; but 2000 minus 1950 equals 50, while 00 minus 50 equals -50. Results like that -50 could lead computers to churn out bogus data or shut down entirely.

Between the days when that programming decision was made in the middle of the the 20th century and the 1990s, computers went from massive machines that were mostly found at government laboratories and universities into a common feature of many businesses and organizations. By the 1990s, computers were doing everything from processing payroll to tracking what grocery stores had in stock to keeping power plants working. Many in IT knew the date-related issue existed, but for years the assumption had been that someone would come along and take care of it before it was too late. But by 1993, the point at which the IT world began to truly focus on the problem, it became clear that there wasn’t much time left before “too late” arrived.

To sound the alarm, some publications aimed at computer professionals used terms like “doomsday” to raise the stakes—but this was not meant as a premonition of defeat but a call to action. While some in IT described the problem as a dragon, they also emphasized that it was a beast that could be slayed, provided that sufficient time and resources be devoted to the task. This challenge was made all the more difficult by a recognition that large computer-related projects have a tendency to take longer than expected and go over budget. But for all of this evocative terminology, by 1995 most people were just calling the problem Y2K.