The millennium bug stems from the way in which computers store dates. In daily life we regularly use a shorthand way of writing dates, using 31/10/97 instead of 31 October 1997. If we need to refer explicitly to dates in the next century we make our intentions clear by writing 31/10/2097.
Much of the computer software written for the mainframe computers used by big businesses was designed using a similar system of date notation with two digits to store the year and, unfortunately, no way of entering a specific century. In the year 2000 these systems will store the year as 00 but will not realise that the century is no longer 1900. This means date computations will give false results. For example, peopleΓÇÖs ages are usually computed by subtracting dates of birth from the current date. This works fine if itΓÇÖs 1997 and you were born in 1955, because 55 subtracted from 97 is 42, but if you subtract a birth date in 1955 (stored as 55) from 00 you get an age of minus 55!
There would be chaos if this type of date - currently used for invoicing, booking systems, interest calculations and a host of other transactions - went uncorrected, and itΓÇÖs by extrapolating the problem to areas such as air traffic control, automated safety systems and international banking that pundits have produced scare stories about ΓÇÿmillennium meltdownΓÇÖ which could cause whole societies to crumble.
