It's more than a decade since the wave of panic over the Millennium Bug - the flaw in modern PCs which was expected to create massive system failures and even worries about errant missile launches thanks to computers confused about what century we were in.

However, the calendar flipped from December 31, 1999, to January 1, 2000, with the world relatively unscathed from the Y2K switchover.

Ironically, the clock ticking to January 19 2038 poses a similar threat to some systems today.

Languages such as C, C++, and early Unix languages stored dates in an odd way beginning in 1970, says Drake Coker, chief technologist for application development at Cobol provider Micro Focus.

That overflows 32 bits on January 19 2038, Coker says. Older software will experience the problem, he says, but it won't be as big a problem as Y2K.

The Y2K countdown: Tech's big drama

If you worked in technology, you might remember that New Year's Day as different from others. Instead of recovering from the previous night's celebrations, you may have had to work or at least be on call to keep watch over potential Y2K-generated mishaps.

For anyone who needs an explanation after all these years, the Millennium Bug referred to computer systems that used two-digit dates because programmers at the dawn of computing did not think far enough ahead to put in four digits.

So when the 1990s made way for the year 2000, the year '99' would become '00', with systems believing the world had just reverted to 1900 instead of advancing to the year 2000.

"The fundamental issue was the date ranges," says Josh Aaron, president of Business Technology Partners, a technology consulting firm.

A now-retired technologist who worked for BT 10 years ago recalls the extensive efforts to tend to Y2K.

"It all got done, and it was a hell of a lot of work involved, and of course once you fix it, you've got to test it," says David Quinn, who ran the systems software group at BT.

Y2K was fixed because people prepared for it, Quinn says.

"I wrote some of those systems [for billing and order management]," he says. "I know the dates were wrong."

A decade after Y2K, technologists reflected back on that time and the lessons learned, with some disagreement over whether Y2K turned out to be basically a non-event because millions were spent in a heroic effort in advance to fix the problem or because the problem was overblown in the first place.

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NEXT PAGE: Was the Millennium Bug blown out of all proportion?

  1. We look at how the web has evolved since the disaster that never happened
  2. Was the Millennium Bug blown out of all proportion?
  3. Two years of preparation