Humble Pi: When Math Goes Wrong in the Real World

by Matt Parker

At 3:14 a.m. on Tuesday, January 19, 2038, many of our modern microprocessors and computers are going to stop working. And all because of how they store the current date and time. Individual computers already have enough problems keeping track of how many seconds have passed while they are turned on; things get worse when they also need to keep completely up-to-date with the date. Computer timekeeping has all the ancient problems of keeping a calendar in sync with the planet plus the modern limitations of binary encoding. When the first precursors to the modern internet started to come online in the early 1970s, a consistent timekeeping standard was required. The Institute of Electrical and Electronics Engineers (IEEE) threw a committee of people at the problem, and in 1971 they suggested that all computer systems could count sixtieths of a second from the start of 1971. The electrical power driving the computers was already coming in at a rate of 60 Hertz (vibrations per second), so it simplified things to use this frequency within the system. Very clever. Except that a 60-Hertz system would exceed the space in a 32-digit binary number in a little over two years and three months. Not so clever. So the system was recalibrated to count the number of whole seconds since the start of 1970. This number was stored as a signed 32-digit binary number, which allowed for a maximum of 2,147,483,647 seconds: a total of over sixty-eight years from 1970. And this was put in place by me...