National coordinators from more than 130 countries met at the United Nations in New York on Friday to discuss contingency plans and crisis management for dealing with the "millennium bug" computer conversion problem, known as Y2K. Addressing the experts, Secretary-General Kofi Annan described the Y2K conversion problem as the most complex problem in the history of computing. If left unresolved, he said, it would impact on everyone's daily life in unknown ways.

Air traffic controllers used handwritten notes to keep track of hundreds of planes over New England and upstate New York when a computer failed, AP quoted The Boston Globe. The problem at the Boston Center in Nashua, New Hampshire, began Wednesday at about 6:50 p.m., one of the busiest times of the day, and lasted for 37 minutes, the Globe said.

Approximately 75 controllers at the center, which controls flights over more than 160,000 square miles of air space, were following about 300 aircraft at the time. Controllers could see the planes as blips on radar screens, but information about their altitudes, speeds, routes and destinations were wiped out by the computer failure.

Imagine what could happen when Y2K arrives.

Peter de Jager, the "world's leading consciousness-raiser for the year-2000 problem," has said that with less than two years left until the world's computers enter the new millennium, the built-in, preprogrammed microchips that run everything from microwave ovens to nuclear reactors have been overlooked or ignored when considering the date-processing errors expected to plague computers after December 31, 1999.

Wired News said that De Jager has started what he calls Project Damocles to prod embedded systems manufacturers to reveal "millennium bug" problems that might affect their products, "from electric razors to heart-lung machines." Dr. Leon Kappelman of the University of North Texas said, "This is potentially the most destructive part of the year 2000 problem. This isn't the inconvenience part where your paycheck comes a few days late. This is the blood-in-the-streets part."

Wired News reported that "embedded systems can be found in all types of power plants, water and sewage systems, many of the devices used in hospitals, military equipment, aircraft, oil tankers, alarm systems, and elevators."

It could be the electricity that goes first--the national power grid brought down by confused microchips. It could be the banks, brought to their knees by befuddled bookkeeping programs that think they've been flung backwards in time by a century. Or maybe it will be the telephone system. Or the stock markets. Government agencies like the IRS. Trains, planes, even some automobiles.

Whatever the order of our going, when the clocks on millions upon millions of computers and digital systems click over to "2000" at midnight on Dec. 31, 1999, we all may go down together.

That, at least, is the pessimistic warning from software management expert Edward Yourdon. There are lots of opinions out there about the so-called "millennium bug" or year 2000 crisis; no one knows for sure what will happen when parts of our vast electronic grid wake up on the morning of New Year's Day, 2000, and can't remember what day it is. But the warning voices are getting louder: Federal Reserve Chairman Alan Greenspan told Congress, "Inevitable difficulties are going to emerge. You could end up with … a very large problem." In the face of such uncertainty, Yourdon's new book, Time Bomb 2000 (Prentice Hall, 416 pages) prescribes some doses of healthy fear.

Don't relax and think, "They'll have it fixed in time," and don't trust the executives and functionaries out there who blandly reassure you that they have the situation under control, Yourdon warns. They are probably simply crossing their fingers. Most companies and institutions got a slow start on the mammoth project of updating all their old software and systems to think of years in four digits rather than two--and in many cases it's already too late to finish in time.

Throwing hordes of programmers at the problem at the last minute is likely to be worse than useless. Rushing a software project, the saying goes, is like rushing a pregnancy--you can't make a baby in one month by putting nine women on the job.

But the real kicker of Yourdon's argument lies in his notion of "ripple effects." Even if your employer, bank, insurance company and electric utility all have their acts together, significant numbers of companies and institutions won't. It will do you no good to shop at a "year 2000 compliant" supermarket if its distributors' computers have gone kaput and the shelves are bare. A company may fix every line of software code on its mainframe computer systems, only to be hobbled by bad code in "embedded systems"—chips that control mundane stuff like elevators and security systems and factory machinery. Even if only a small percentage of companies get into trouble, in today's economy we're all connected—and just a few percentage points of year 2000 trouble could spell recession or worse.

While the book doesn't outright predict "a moderate, serious or devastating collapse of the nation's socio-economic system," it's chilling that it even brings up the possibility. Even if the worst-case scenarios never come to pass, Yourdon argues, "It's better to be terrified now."

He has acted on his own advice, trading in a New York City home for one in New Mexico--on the theory that Manhattan will be the worst place in the world to be in the event that our economic infrastructure collapses.