Year 2000 problem

The year 2000 problem, also called millennium bug or Y2K bug (from English Year 2 kilo = 2000 ' ), is a computer problem that is caused by the treatment of the annual numbers as two-digit within computer systems.

Causes

In the 1960s and 1970s, space was scarce and expensive. For example, punched cards could save only 80 jobs, computers had RAM with eg 64 kilobytes size. Therefore, programmers saved as much as possible to memory requirements. Therefore were often for storing and processing of annual numbers ( in decimal ), only the last two digits (year and decade, for example, in the format DDMMYY ' or similar. ) Is used, among other things, the computer pioneer Grace Hopper in the development COBOL. The problem affected operating systems, application programs and data resources. The first two digits ( the name the century ) were not considered, and not considering that or whether the programs would be used over the current century addition in this way. Many programs (and the associated data sets ), however, were expanded based again on previous versions over the years, without it, would have been known defect ' corrected. The closer the turn of the century came, the clearer that these programs the year 00 ( and following) in many cases fail to handle.

Not so directly connected, but if necessary, often corrected or controlled at the same time was a sometimes unnoticed leap year rule of the Gregorian calendar. After this round centuries are not leap years unless they are divisible by 400, which after 1600 only in 2000 again was the case.

Consequences / problems

The consequences of this error would be, for example, been wrong sorts without corrections: data for (20 ) 00 up front, ... ( 19) 98 ( 19) 99 in the back. Especially the incorrect calculation of the time period ( calculated as the difference between two times ) would have led to serious errors in many functions. Examples: Age calculation with ' -40 years ' (= Jahr_heute (00 ... ) minus year of birth (40 ) ); Arrears is not recognized ( today date minus date of the payment due date will result in negative day number, reminders only from residue 30 days or more, thus ' no warning '); Debit interest on savings or interest credited for lending rates (due to the negative number of days in the Interest formula ) and a v.

Furthermore, it was widespread practice, non-existent or invalid data contents with the number or combination of numbers 00 ( "Nothing " ) represent and identify - what would then have led to the occurrence of 2000 to misinterpretation, possibly all, even for non-processing, supposedly invalid records. In addition, there were defective production of texts (a typical example would be a date with the year " 1901 " or " 19101 " for the year 2001).

At that time older PCs was that the internal clock does not automatically could switch the century, which was not yet 98 corrected automatically by the BIOS of MS- DOS or Windows. Specifically computer-controlled hardware components (so-called embedded systems, Eng. Embedded systems, such as burglar alarms, video recorders, machine tools ... ) could pose problems, since the user could not simply reprogram the software, but this is by the manufacturer ( if still available can do ), or even had to replace the hardware.

There were several strategies to circumvent the year 2000 problem (eg year > 50 is considered 19xx, otherwise known as 20xx with less long-term durations, data fields on four-digit years or other date formats change ), users had adapted exactly to plan, in which contexts which of these strategies was applied. There were many programs that processed many data sets had to be ensured that changed programs always presuppose also correspondingly changed data sets. Difficulties arose in this context for a historical data base: This had to be decided whether this should also be adapted or whether they had to be processed through old ( unmodified ) versions of the program.

Among other challenges enterprises were partly faced with the situation of not knowing what programs work and which devices dates at all and then are year 2000 compliant. This could lead to extensive collection and testing measures to significantly more overhead caused usually as correcting faulty software.

History

Because of these problems 2000 disaster scenarios were before the New Year 1999 / predicted that computer crashes would be in great measure by this error. In what would be the Y2K problem of real relevance, was to evaluate the late 1990s hardly realistic.

There were voices in the media, the scenarios of apocalyptic proportions predicted with global computer breakdowns. Therefore should be concerned particularly sensitive areas that are dependent on computers (banks, industry or power plants, nuclear weapons even in the most extreme case, the predictions), lack switched by the problem or would even paralyzed. The consequences were led many scenarios from traffic and a stock market crash and a global economic crisis to false tripping of nuclear weapons systems - even plane crashes, although time error at this time were part of the certification procedures for security-critical software long ago.

Careful analysis by experts showed quite back to real dangers, especially for businesses.

In virtually all large companies a close examination of computer systems has been arranged using diagnostic procedures in order to keep the feared consequences as low as possible. Also warning stickers were distributed for those devices that have been taken by the end of 1999 systematically from the operation.

The software industry responded with a review of their products and issuing of warning lists which programs malfunctions are to be feared. These were combined with the test routines for the hardware (in particular, the system clocks ).

Private users found on the Internet lists of endangered hardware and software.

While some media had spread until the critical year 1999/2000 concerned reports, in early 2000, but found that the precautionary measures on the whole, had been sufficient: Worldwide, in many projects, programs and databases (especially on mainframes ) " rehabilitated "to the " to avoid Y2K bug ". However, many banks had New Year's Eve just parked their ATMs to avoid errors.

Occurred reported problems

None of known year 2000 issues had a major impact. They performed well in countries such as Italy, which had little invested in the correct the problem, sparse on. Here are some examples:

The United States Naval Observatory, the official timekeeper for the United States, announced on its website the year 19100.
In Australia, the bus ticket confirmation machines failed.
In the United States fell more than 150 slot machines out of racetracks in Delaware.
In Italy, Telecom Italia sent bills for the first two months of 1900.
In Japan fell on 1 January 2000 out of the system for recording flight information for small aircraft.
In Spain, was summoned for 3 February 1900 an employment tribunal date.
In South Korea, the district court invited 170 people to the hearing on 4 January 1900.
In the United Kingdom fell from some credit card transactions.

Economic aftermath

Due to the hardware and software updates that have been made to prevent the Y2K problem, many users were equipped with current platforms in 2000. This triggered the following four- year period ( life of a common office equipment ) a slump in sales of new systems and a noticeable recession in computer science area.

The cost to the economy were enormous. It has been estimated, for example, from the Massachusetts Institute of Technology, that only the U.S. Medicare program had to spend 500 million U.S. dollars to resolve the error. The total cost of the Y2K projects was estimated by Gartner in the world, " up to 600 billion U.S. dollars," in large companies reached the cost of measures to review and change the applications, two - to three-digit millions of euros ( EUR ).