Understanding the Year 2000 Problem Overview. The so-called Year 2000 or Millennium Problem has been a focus of widespread public concern and media attention. The Year 2000 Problem is the term used to describe miscalculations in applications expected to occur when the calendar flips from 1999 to 2000. Because the first two digits are omitted, many computers will be unable to tell whether it is 1900 or 2000 when the new century arrives. If a computer mistakes 1900 for 2000, the result will be miscalculations for all date dependent applications.
Any calculation involving dates can go awry.
Computers may fail to display the correct date or fail to distinguish which of two dates comes first, misinterpret people's ages, or miscalculate time intervals. These types of mistakes will lead to errors in such things as interest rate calculations, credit card account information, delivery and billing dates, inventory control, and ticket reservations and issuance. Of course, the Year 2000 Problem affects only computers that treat the year as a two-digit number. For computers that use four digits, there is no problem unless the software application or operating system also has a Year 2000 Problem. However, such a system may still generate incorrect output if it receives two-digit numbered date data since such system would then lack adequate information to determine the proper century.