What is the millennium bug?

The millennium bug, also referred to as the Y2k, was a problem that arose because computers in the 20th century used only the last two digits in year designations when storing dates. So, for example, 01-01-1984 was stored as 01-01-84. With the entry of the new century, the problem would arise that computers would get ‘confused’ because we now went from 01-01-1984 to 01-01-2084, but this difference could not be noted.