Y2K - Definition

The Year 2000 problem (also known as the Y2K problem, the Millennium bug, the Y2K bug, or simply Y2K) was a problem for both digital (computer-related) and non-digital documentation and data storage situations which resulted from the practice of abbreviating a four-digit year to two digits.

The millennium bug was specifically a programming problem. It was the result of a combination of a space issue as well as a lack of forward thinking on the part of the programmers back in the 1960s and 1970s. During the beginning stages of computer programming, memory and other storage space were scarce and expensive, so saving characters were a priority. This results in the possibility of a date such as 31 being misinterpreted (is it 1931 or 2031?). Thus, any computer program which deals with 6 digit dates is susceptible to the Y2K problem.

The Y2K problem involves two key date issues:

1. Date mathematics. For years businesses have used date math to compute things such as aging schedules, due dates, past due accounts, etc. Many computer applications now Support the use of date mathematics (Lotus 1-2-3, MS-Excel, MS-Access, etc.) These applications all work by using a base year (often Jan. 01, 1900) as a starting point and then tracking the date and time numerically from that point (how much time has elapsed since Jan 01. 1900). Thus, a time might be stated as a fractional component of the day integer (35927.63 = May 12, 1998, 3:08 pm based on MS-Excel). This means that to compute the difference between Jan 01, 1998 and Jan 01, 1999 would result in 365 days. Computing the difference in today and when a bill was incurred would indicate how old a debt was (e. g. 45 days = past due). So, when the year 2000 comes into play using a 6 digit date we end up with situations like Jan 01, 00 - May 12, 1998. If this is misinterpreted by a computer system as 1900 then the calculation will result in a large negative number (in this case -35,926). This number may or may not be a problem the computer application can deal with. It is possible that this number will be made into the absolute value (the negative sign is dropped if no space is reserved to hold it) which will cause even more confusion. Imagine if your debt went from 22 days old to 35,926 days old. The past due notice would give you a surprise.

Thus, the main problem of Y2K is the problem of incorrect results when date mathematics are conducted. Most companies are working to correct these problems in their COBOL programs and most current microcomputer applications already have built in fixes.

2. The second type of problem involves systems that check the date for some purpose to determine if a valid date is being used. An example might be a credit card Expiration Date. If the program that checks this when the card is scanned is very simple it might just say is today greater than the expiration date. Thus, 01/01/99 is greater than 01/01/00 which would result in your credit card being rejected. Another example is a security system which checks to see if today is a valid date before recording an entry or exit from a building. If the 00 date is determined to be out of Range or the computation is at fault the system may simply shut down and lock all the doors.

Terms near "Y2K"

Yale School of Management - Yale SOM

Yankee Bond

Yankee Certificate Of Deposit

Yankee Market

Yard

Year over year (YOY)

Year to Date (YTD)

YER

YER

Yield