Leap year bug
Leap year bug (also known as the Leap year problem) is a problem for both digital (computer-related) and non-digital documentation and data storage situations which results from the wrong calculation of which years are leap years.
Type
There are several types of leap year bugs.
- Some digital systems have ignored the existence of leap years. Therefore, when the date is February 29, the system would wrongly treat it as March 1.
- Some digital systems have wrongly calculated which years are leap years. The best-known case occurred in Sony's Playstation 3: The system treated 2010 as a leap year, so a non-existent date February 29, 2010 was shown on March 1, 2010, and caused program error.
- Many digital systems will face a leap year bug, known as the Year 2100 problem. Although most years that are evenly divisible by 4 are leap years, years that are evenly divisible by 100 are not leap years (unless they are also evenly divisible by 400). Therefore, 2100 is not a leap year. If a system simply treats all years that are evenly divisible by 4 as leap years, which would work for many computer systems around today since 2000 was evenly divisible by 400, a non-existent date February 29, 2100 will be shown on March 1, 2100. Systems that pre-date general awareness of the Y2K bug, and systems that have been created since 2000 that have not had to deal with pre-2000 dates, will face a combination of Y2K and the leap year bug if they are still in use when 2100 approaches.
See also