Note: This article was written before the year 2000.
The year 2000 bug
The year 2000 bug stems from the fact that on many computers, dates are given in two figures, so instead of displaying (calculating) 4 figures (e.g. 1974), these computers display 2 figures (e.g. 74).
This is because when these computers were manufactured memory was expensive, so programmers and manufacturers tried to save on memory as much as possible.
For this reason, when the year 2000 arrives, at 11:59:59 pm on December 31st 1999, computers and all elements with dates coded in just 2 figures will switch from the year 1999 to the year 00, which for the computer will mean 1900.
This will also pose a problem for elements that use the system's time and date, particularly to calculate a duration by making a subtraction, or software programs that perform automatic tasks on specific days of the week (January 1 st 1900 will be a Monday whereas January 1 st 2000 will be a Saturday).
To further complicate matters, the year 2000 is a leap year, whereas 1900 wasn't; thus in 1900 there were 28 days in February and there will be 29 days in February 2000.
On January 1 st 2000, many computers and systems that operate randomly according to the operating system clock will operate incorrectly or will quite simply stop working. These inconsistencies may range from minor or simple errors to the shutdown of an entire workshop and other problems involving ecology, defence, industry and the stock market.
This is why many code lines (millions in fact) must be changed (for the programmes) and patches (software corrections) must be installed on many machines to prepare them for this critical changeover.
El error del año 2000
Le bug de l'an 2000
Millennium bug (Bug dell'anno 2000)
O bug do ano 2000