The media has concentrated primarily on the big issue, the fact that many computer
systems have only stored dates with two digit years. While this is probably the
biggest problem with the broadest reaching effects, there are four dates during 1999-2001
when computer programs may fail due to bad date-handling. In this section, I'll
briefly explain the problems and what systems may be effected. The problems are
listed in the order in which they will occur.
GPS Rollover
When September 9th = EndOfFile
Year 2000, the Biggie
Yes, 2000 is a Leap Year
And a Leap Year Has 366 Days
It Never Rains, But It Pours: Solar Storm Predictions
And For Extra Chaos, Bad Calls to the RTC 
What Might Happen
GPS Rollover
GPS stands for Global Positioning System, a set of satellites designed to help locate
ships, airplanes, trucks, and anything else carrying a transponder. Orbiting the
Earth, they rely on an old method of pinpointing one's position (triangulation) with a new
twist (from high altitude). It's a very popular process. In addition to the
department of defense, an estimated ten million commercial planes, ships, and private
individuals use the GPS system for navigation.
On board each GPS satellite is a very accurate atomic clock. GPS measures
seconds, minutes, hours, days, and weeks since the system was started on 5 January
1980. It tracks the number of weeks in a register that can hold a number from
0-1023. Instead of going to 1024, it goes back to 0, like a car with 999,999 + 1
mile. The GPS satellites will rollover on 22 August 1999.
The GPS system is used to determine dates as well as location on millions of
navigational units around the world. It is also used as a method of recording
time-of-day by many non-transportation systems, including many major banks in the U.S.
It is unknown whether or not these systems rely on GPS for date information as
well. It may very well be that many banking computers will not know the difference
between 22 August 1999 and 5 January 1980. Perhaps you will be charged for 19.5
years of unpaid interest. Perhaps you bank will have to reset its computers.
Perhaps your bank will have to close for the day. Not a pleasant thought if you
planned to buy groceries with your ATM card.
And, let us not forget the possibility that major transportation systems like
commercial aviation, shipping, and trucking may be shut down or delayed by problems in the
GPS. For more information, see What Might Happen.
Resources
All About GPS - An
in-depth site with step by step explanations of the GPS system, from Trimble Navigation Limited, a company
which specializes in GPS equipment
GPS Joint Service System
Management Office (link no longer valid) - The military department that supports GPS user equipment for all
services.
Millennium
(Y2K) and GPS End of Week (EOW) Rollover (link
no longer valid) - A presentation by Capt. Jason Christ, GPS
Y2K Lead Engineer, Navstar Global Positioning System, Joint Program Office
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When September 9th = EndOfFile
On 9 September 1999, the shorthand representation of the date will be 9/9/99. The
problem is that '9999' is a code in many COBOL programs
which means "End of File."
Non-compliant applications can store dates in many different formats: MMDDYY and YYMMDD
are probably the most popular (9 September 1999 stores as 090999 or 990909). It is
possible, however, that some systems are designed to handle date inputs of 9/9/99 and
convert it to either of those two forms. In this case, it is possible that 9/9/99
might be interpreted as an instruction to end the program running. A minor
possibility, but one that must be anticipated and planned for.
Resources
99 Bug to Precede Y2K Bug
- An article in the Washington Times about 9/9/99 (and 1/1/99)
Y2K The
Millennium Bug, part 4: "Other" Date Issues (link
no longer valid) - A comprehensive section
of a fantastic site.
Year 2000
Technical Resource Center (link no longer valid)
- Developed for the U.S. Army's Year 2000 task force by the
Technology Integration Center.
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Year 2000, the Biggie
In case you haven't heard, the cost of computers is dropping like a rock.
Just ten years ago $250 would have bought you a 170 Mbyte
hard drive. These days it will buy you a 6 Gbyte
hard drive. Today, you can buy a computer with a 4 Gbyte hard drive and 32 Mbytes of
RAM for about $1000. In the mid-60's
a computer with a 2 Mbyte hard drive and 32 Kbytes
of RAM cost about a million dollars! Naturally,
anything that programmers could do to save a few characters in RAM and on the hard drive
was gratefully appreciated. It was expected that the programs developed in the
mid-60's would most likely be replaced in the 70's. No one expected that they would
still be in use at the end of the 90's.
Dates all through the computer industry are stored with only two digits representing
the year. When dates are stored with the full four-digit year, the programs are
designed to communicate with their impaired brethren.
Consider the following true story. A 103-year-old man joins an HMO. He
gives his birthdate, including a year that begins with 18__. The HMO has a two-digit
field to store year-of-birth information. The HMO's computer decides that the man is
three years old and assigns him to a pediatrician.
The big problem surrounding the Year 2000 will involve time periods that cross the date
line. It is obvious that a child born 1/1/2000 will be three years old on 1/1/2003,
but how will a computer interpret the age of a child born 1/1/1999? A compliant
computer will correctly interpret the child's age as four years old. A non-compliant
computer may interpret the child as being 96, or -96, or maybe even -32,764 or -65532.
(For an explanation, click here.) Maybe the computer will shut down with an "invalid
age" message. What if the computer belongs to an HMO that processes ten
thousand customer records per day, most of them for children older than four?
An HMO's computer system is not really critical (unless you are having chest pains and
trying to get permission to go to the emergency room), but what if the electric company
decides that you haven't paid your bill on time (in 99 or maybe 32 thousand years).
All sorts of situations can arise. These are discussed in What
Might Happen.
Resources
Peter de Jager's official Year 2000
site (link no longer valid) - The ultimate reference by the man who broke the story back in 1993, in an
article appropriately titled Doomsday
2000.
Edward Yourdon's Web Site
- Edward Yourdon is the brilliant co-author (with his daughter Jennifer of Timebomb
2000, which I feel is the definitive book on possible outcomes of the Y2K crisis.
Early
Year 2000 Glitches Provide Sneak Preview - CNN reports that early detection helps
promote the cure.
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Yes, 2000 is a Leap Year
It seems strange, but many people are still confused over whether the year
2000 is a leap year or not. We all know that when a year is divisible by four (as
was 1996) it is a leap year. But there is an exception. When a year is
divisible by one hundred (as was 1900) it is not a leap year. But there is further
exception. When a year is divisible by four hundred (as is 2000), it is a leap year.
The best (and funniest) explanation of the reasoning
behind this was supposedly written in the help desk of Digital Equipment Corporation in
answer to a complaint that their VMS operating system treated the Year 2000 as a leap
year, which the complainant incorrectly thought was in error.
Systems which correctly interpret 01/01/2000 as part of 2000 and not 1900
may still think that 28 February 2000 is followed by 1 March 2000.
Resources
Year
2000 Issues: Leap Year Problems and Resolutions (link
no longer valid) -
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And a Leap Year Has 366 Days
Some computer programs keep track of the Julian date, that is the number
of days in the year. 5 January would be 005, and 20 July would be 201. If made
Year 2000 compliant but not leap year compliant, these systems would handle correctly
handle 29 February 2000 as 2000060, but would be stuck when confronted with the fact that
2000365 is 30 December, not 31 December.
The Year 2000 problem will not be over until 1 January 2001.
Coincidentally or not, that is the true start of the next millennium.
Resources
Leap-Year
software bug gives "Million-dollar glitch" - A computer program that didn't
understand that 1996 was a leap year underwent massive system shutdown on 31 December 1996
at two aluminum smelting plants in New Zealand and Tasmania. By the time the bug was
discovered and corrected, both plants were damaged to the tune of one million New Zealand
dollars.
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It Never Rains, But It Pours
One of possible results of the Year 2000 crisis is a disruption in power,
either because of problems in the computer systems that provide the power or in the
computer systems that bill you for your power consumption. As an extra irony, we may
lose power even in Year 2000-compliant systems.
During periods of high sunspot activity, the magnetic particles emanating
from the Sun are increased. The increased particle output affects our Earth's
atmosphere. The Aurora Borealis is brighter and more vivid. The
atmosphere expands. (A higher than normal sunspot season is blamed for the early
re-entry of Skylab.) The average temperature drops. And magnetic storms
disrupt power transmission. The risk of Solar storm interruption of power is
increased in Northern cities. Ironically, the regions that will be coldest and most
likely to need power for heating are most likely to lose power during a solar storm.
NOAA's Solar Cycle 23 Project predicts that there will be a sun spot
maximum from January 1999 through January 2001. In addition to the obvious problems
this may cause in power transmission, sun spots interfere with satellite transmission, and
may cause additional problems in communicating with the GPS satellites. We'll be
well into solar maximum when the GPS date rolls over.
Although I am writing this in August of 1998, about six months before the
normal beginning of the solar peak, I am informed by a friend who works for Southern
California Edison that a memo advising them to be on the lookout for solar storm-related
blackouts. This solar maximum shows signs of being unusually strong.
Resources
Solar Eruption Causes
Geomagnetic Storm on Earth
Solar
Cycle 23 Project
Cosmic
Storms Coming: Violent Outbursts of Gas From the Surface of the Sun Could Lead to Big
Trouble Here on Earth (link no longer valid) - An article from Time magazine, 9 September 1996
Upon completion of the engineering tests, Skylab was positioned into a
stable attitude and systems were shut down. It was expected that Skylab would remain
in orbit eight to ten years. However, in the fall of 1977, it was determined that
Skylab was no longer in a stable attitude as a result of greater than predicted solar
activity. On July 11, 1979, Skylab impacted the Earth surface. The debris
dispersion area stretched from the Southeastern Indian Ocean across a sparsely populated
section of Western Australia.
-- from NASA's Skylab Operations
Summary |
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Page
And For Extra Chaos, Bad Calls to the RTC
Your computer keeps track of the date and time with a module called the
Real Time Clock. Microsoft says that Windows NT™ prohibits direct access to the
Real Time Clock. Instead, applications are supposed to ask Windows NT™ for the
date or time.
Most Real Time Clocks are not Y2K compliant, but that shouldn't be a
problem. Windows NT™ understands that when Real Time Clock says '00' that it is
2000 instead of 1900. The problem is that some programs, especially those that
require precise date and time information, access the Real Time Clock directly.
These programs may not be compliant.
As if we didn't have enough problems.
Resources
Scope of Y2K Crisis Widens: Clock Problem Found
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Resources for Other Problems
January
1, 2000 Isn't the Only Doomsdate (link no longer
valid) - Covers the above, plus UNIX EndOfFile (8 September
1991), UNIX rollover (19 January 2038), and the Social Security and telephone providers
running out of numbers.
What Might Happen
Now that we've examined the causes of our woes, let's take a look at what
might happen if these issues are not resolved.
Next
