The millennium bug or the Y2K bug was going to cause planes to fall from the sky, bank accounts to be wiped out, electricity grids to cease functioning, trains to crash, cars to collide as stop lights stopped functioning, life support units to malfunction and computers to crash around the globe. For years leading up to midnight on New Years eve 1999 consults were paid extraordinary amounts of money to solve the problem. When the clock ticked over to 1st Jan 2000 nothing much happened. It was, indeed, a non-event, an error in logic. (Pic from, appropriately, digyourowngrave.com)
Computer programmers represented the year in the date of many programs using two digits but claimed logical errors would arise upon “rollover” from x99 to x00.
While consultants claimed their advice saved the world from catastrophe countries that spent very little on the Y2K bug problem (eg. Italy and South Korea) experienced as few problems as those who had spent a good deal of money on the bug eradication namely USA and UK. The solution: Don’t guess. Test parts of system by plugging in x00.