Year 2000 problem   Y2K problem, or millennium bug, in computer science, a design flaw in the hardware or software of a computer that caused erroneous results when working with dates beyond Dec. 31, 1999. In the 1960s and 70s programmers who designed computer systems dropped the first two digits of a year when storing or processing dates to save what then was expensive and limited memory; such a system recorded the year 2000 as 00 and could not distinguish it from 1900. In sorting, comparison, and arithmetic operations, the year 2000 would be treated as if it were equivalent to 0 rather than 100, causing incorrect results. The algorithm used to calculate leap years was also in some cases invalid, creating an additional problem in calculating the correct date after Feb. 28, 2000. Because the designers of such computer systems expected them to be replaced before the beginning of the year 2000, using a two-digit date was not regarded as a problem. Thousands of older computer systems, called legacy systems, were still in use in the 1990s, however, particularly in the finance and insurance industries, creating a potential operational and financial nightmare, which was termed Doomsday 2000 . In the late 1990s business, government, and other computer users spent thousands of hours and millions of dollars to correct the Year 2000 problem, and only minor problems were experienced after Jan. 1, 2000.

Millennium bug The problem faced by computer users when the year 2000 (y2k) was reached. Many accounting and database applications had, for years, used only two digits to represent the year in a date; i.e. they would use 31.12.99 to represent 31 December 1999. This would obviously give incorrect follow-on dates for 01.01.00, and incorrect sorting of records in date order. Another problem involved the BIOS giving incorrect dates after 31.12.99. A considerable amount of money and time was spent by companies preparing for y2k. Most problems were solved by new software issues or by patches to existing software, and the major disruption that many had predicted did not materialize.

Millennium Bug

The millennium bug refers to the existence in many computer software packages of a six-digit date rather than an eight-digit date. Computers speak the language of mathematics. Every question posed to a computer program is answered either "yes" or "no" and represented in binary code as either a one or a zero. Since computers recognize math symbols, a computer can add 97 + 1 and get 98. When the computer is presented the problem 99 + 1 and the answer does not fit in the required two-digit field, the computer's response is an error, or worse, a shut-down.

What caused this error in planning to occur? In the 1960s and 1970s, when computers were coming into widespread use, one of the largest concerns to programmers was the amount of memory available to the user. With this concern in mind, programmers searched for ways to cut memory requirements. Reducing dates to six digits (01/31/99, for example) rather than using the eight-digit international date (01/31/1999) was one way to decrease memory requirements. A second reason is that computers were so new and programmers were so inexperienced that they believed that any software produced in the 1960s and 1970s would be archaic by the 1980s and certainly long before the year 2000. They produced software designed to answer immediate needs, failing to predict that software programs would be used far longer than intended.

Many businesses and industries were impacted by the millennium bug. All entities that work from a mainframe were vulnerable, including many government agencies, such as the Internal Revenue Service and the Social Security Administration among others. Any business or entity using personal computers (PCs) was vulnerable. Computer experts estimated that 93 percent of the PCs made before 1972 would fail. When PCs are part of a network, the risk of problems developing is much greater.

Many doomsday predictions were made prior to January 1, 2000. Books, videos, and web sites, all designed either to sell consumers the equipment needed to get them through the "apocalyptic" event or to warn computer users what to expect, began to appear. Almost weekly, newspaper articles were published reporting who had done—or had not done—what to prepare and what types of tests had succeeded or failed. During the final week of 1999, local governments suggested that citizens stockpile drinking water. It was predicted that businesses dependent upon computer systems would fail. Some people feared runs on banks by panic-stricken people that would put the national economy at risk of collapsing. Public and private transportation would shut down due to fuel shortages resulting from delivery problems and electrical failures. Hospitals, governing agencies, the food industry, news, communications, and education were predicted to suffer due to the millennium bug.

The millennium bug dilemma appeared deceptively simple: After all, how difficult could it be to change programming to read a four-digit year rather than a two-digit year? The situation became more complex due to the magnitude of programs that needed to be changed. Every mainframe computer, every program created before 1995, the vast majority of PCs made before the mid-1990s, every microchip embedded in every car, every pacemaker—all of these only begin a list of the things that could potentially be affected by the millennium bug. The challenge of fixing all of the potential problems before January 1, 2000, seemed impossible. Information technologists would have to check every system for compliance. The problem, which existed not just in the United States but across the entire globe, seemed astronomical.

At the end of 1999, the computer industry was expected to spend between $300 to $600 billion to deal with the problem. The director of the Millennium Watch Institute said: "Responsible estimates of what we collectively paid … range from 250 gigabucks to 600 gigabucks—enough to give $100 to every human alive. Another estimate mentions one terabuck as a reasonable figure." (A gigabuck is equivalent to one billion dollars and a terabuck is equivalent to one trillion dollars.)

So what did occur on January 1, 2000? A German businessman found an additional $6.2 million more dollars in his bank account than he truly had. A U.S. defense satellite was out of commission for three hours. Amtrak lost track of some trains until the date was reset in the company's computer system. A newborn baby in a Denmark hospital was registered as 100 years old. The doors on a federal building in Nebraska flew open. A government official in Slovenia was forced to resign for overemphasizing the potential problems of the millennium bug, and a few small inconveniences occurred elsewhere in the world. But amazingly, none of the predicted disasters came to pass. Some contend that the Y2K (Year 2000) problems were not severe due to the extensive upgrades that businesses and individual consumers made to their hardware and software prior to the date change.

Some good did come from the preparation. Many companies and government offices are now much more efficient and have developed better communication skills. Software quality has improved. Old hardware has been updated or replaced. Audits have been performed at many companies and agencies, leading to streamlining processes. Information technology experts have acquired much more precise knowledge of systems. According to experts, the modernization that came with the millennium bug preparation will bring economic gains. In the words of one columnist, the millennium bug preparation was "the greatest technological housecleaning of all time."

The extensive hardware and software upgrades by businesses and private citizens also meant that many technology firms saw greatly increased profits during that time. Once systems were Y2K compatible and the intense demand for new products and services decreased, some technology companies began to experience much lower sales and profits than expected in 2000 and 2001.

see also Computers and the Binary System.

Susan Strain Mockert

Bibliography

Chaney, Warren H. Y2K: A World in Crisis? Alvin, TX: SWAN Publishing, 1999.

Yourdon, Edward, and Jennifer Yourdon. Time Bomb 2000. Saddle River, NJ: Prentice Hall PTR, 1998.

Internet Resources

Y2K Media Watch. <http://ojr.usc.edu/content/y2k_briefs.cfm>.