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The following Y2K material has been kept available by MITRE for historical purposes only and has not been updated unless noted.

Testing Leap Year

Be Careful When Testing Out Your System's Ability to Handle Year 2000!

You should back up everything before attempting this since some programs create reference files and they will probably fail to work after you have run this experiment.

The problem will arise when the date is reset to the present and the program tries to use reference files from years in the future (or years in the past if the rollover failed). Additionally, some software uses date checking for licensing purposes and they may expire the license and not allow access after you have set dates into the future.

You can affect the system date change (on Intel-based PCs) as follows: use the configuration utility that sets the time and date or execute the DATE command in DOS Version 3 Release 3 or later.

Test the setting and display of special dates, including:

• 1900/2/29 should fail - the year 1900 is not a leap year
  
  
• 1996/2/29 should succeed - the year 1996 is a leap year
  
  
• 2000/2/29 should succeed - the year 2000 is a leap year
  
  
• 00/01/01 should display an unambiguous 4-digit-year date, the value of which depends on the application. For example, 1900/01/01, 2000/01/01, and so on.
  
  
• 1999/12/31 should be able to distinguish between a regular end-of-year 1999 date and a special meaning date. For example, a never-expiring date indicator.
  
  

For rules on determining whether the current year is a leap year, see Calculating Leap Years. For information about date transition vulnerabilities, see Critical Date Transitions.