Why computers will have a problem with the year 2000
The Y2K problem is linked to the method of data storage and
interpretation used by computers. Many computers keep track of the current date, but the
way that the computers represent the date internally which can be problematic. To a computer,
nearly every piece of information is stored as a number of some kind. A computer does not
actually understand the passage of time, but instead keeps track of a number which represents the
date. As time passes, the number grows larger, so that a date in the past would be represented as
a smaller number than a date in the future. For example, dates might be represented as a number
of the form yymmdd, so the date of August 8th, 1978 would be 780808, while January 22nd,
1999 would be represented as 990122. Most people would know that the year 1999 is after the
year 1978, but the computer can only tell by comparing the two numbers and finding which is
larger. However, as of January 1st, 2000, that comparison will be off by a large amount, as that
date is represented as 000101, even though people would know that 2000 comes after 1999. To
a computer, the date appears to be January 1st, 1900.
What's so bad about 1900?
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Anyone paid his bills the last 100 years?
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A bystander might wonder how having the date wrong in a
computer could cause so much trouble. After all, who really cares if the date at the top of an
essay is automatically set to 1900? The user can just erase that number, and type in the number
2000, right? While it might be possible in that instance, it isn't always that easy. Computers
around the world are running billions of lines of code, some of which have been in use for
decades. It is hard to tell where an altered date may throw the entire system out of whack. For
example, a computer that is used by a utility company might be programmed to automatically shut
off the power to consumers if they haven't paid any bills in the past six months. The computer
may look at the date (recognizing it as 1900), see that no bills have been paid in the past 6
months, and shut off its entire power grid.
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What else might cause Y2K problems?
Another technical reason why this problem occurs is that many programmers may have
hard-coded part of the year rather than risk having to input it every time. As a result, the year may be
represented in the computer as a number of the form 19xx, where only the tens and ones digits are
ever changed. While this problem is slightly different from the other problem, it still causes
computers to think that they are in the past; that it is the year 1900.
Some organizations have known about these hazards for years. In 1989,
America's Social Security Administration tried to set up a payment schedule that ran beyond the
end of the century. The computer system could not process it. This prompted the SSA to start
combing through the computer code it relies on to make 50m payments a month. Visa, a big
credit-card company, also spotted the problem early, but not quite early enough: for almost six
months last year, it had to stop issuing cards with expiration dates in 2000 for fear they would be
rejected.
Computing processes are linked
Large and prominent software companies such as
Hewlett Packard, Oracle, and the like, have also recognized the Y2K problem, and have taken
steps to correct it. But, there are still all kinds of computer-computer interactions which can't
be expected to function properly without an accurate and SYNCHRONIZED measure of the
date. Synchronized in this case, means that two computers must have a relatively similar
representation of the date if they are to interact properly together. Being out of sync by a minute
is inconsequential, but as the time-span increases, so do the interaction difficulties. It is difficult
to envision what problems might possibly occur if two computers believe that they are separated
from each other by 100 years. Take as an example, an ordinary company, which orders the parts
it needs electronically, assembles its product, and then sells its product through some electronic
means such as over the Internet. Even if this company is 100% prepared and its software is all up
to date for the year 2000, there is still a likelihood that its suppliers might be experiencing Y2K
problems. If this company places an order with its supplier for goods to be delivered in the year
2001, those goods might not be sent for 100 years, if they are sent at all. It is also possible that its
consumers might not be fully Y2K compatible either, and might request that goods be delivered in
the year 1901, because their computers do not know the correct date. Thus, because of the many
linked computer processes that depend on having nearly synchronized representations of the date,
this company will have no means of making money, even though it may be ready itself to handle
business in the year 2000.
