All yesterday, the White House's Y2K command center watched the world's time zones. It was a hushed, efficient operation, sort of like a bank on a busy day. But a buzz finally began--after midnight.

About 200 staffers still on duty tried to sort out conflicting reports and run down rumors. They were making one last push to collect data on East Coast and Midwest power, telephones and major industries in the early hours of New Year's Day before confronting an onslaught of Y2K reports from the West Coast.

The buzz, though, was sedate by standards being set elsewhere in Washington. With booze banned on federal property, staffers made do with cake and televised fireworks for a midnight celebration.

John A. Koskinen, the president's Y2K troubleshooter, appeared in the center's press room just before midnight with a chocolate cake with "2000" written in multicolor icing. Koskinen bantered with reporters and briefly held the cake aloft for the television cameras.

Much of the day for Koskinen and his staff was spent searching for patterns that would give meaning to the year 2000 computer glitch. Except for a jet flight to New York and back in early evening to show his confidence in the nation's air traffic control system, Koskinen spent much of his time inside a glass-walled office sifting through Y2K information collected by the government, foreign nations and industry groups.

Outside the glass office, government and industry experts worked at 100 flat-screen computer stations, receiving and forwarding data. Two floors up, television crews and reporters waited for updates in a makeshift newsroom littered with its own high-tech equipment.

Koskinen, despite a day of mostly positive Y2K reports, remained ever cautious, refusing to declare immediate victory over the so-called millennium bug, the glitch that threatened computers that might interpret "00" in their software as 1900, not 2000.

"The degradation of service may take two or three days in some of these countries to show up. What they are going to lose is not the dial tone, they are not going to lose power production. What they are going to lose is monitoring processes, billing and related control processes," he said in a hallway interview.

"So in some ways it is going to be less exciting than everything turning off at one time," he said. "On the other hand, it is a much more difficult, complicated process because you've got to collect this kind of information from everywhere to see if there are patterns, are there issues? Do we really know what is going on out there?"

Koskinen had pulled together an operation rarely seen in peacetime. He had Cabinet departments, intelligence agencies, industry groups and experts reporting to the $50 million command center, modestly named the Information Coordination Center by the White House.

The center included a secure room where military and intelligence officials could brief Koskinen and his staff on Y2K and related troubles, such as any cyberattacks and terrorism.

Koskinen worked from a private office large enough to hold a conference table for meetings. Late at night, he played classical music on his computer and kept up with his e-mail. Don Meyer, an aide to Sen. Robert F. Bennett (R-Utah), chairman of the Senate Y2K special committee, said the floor where Koskinen meets with his staff was "very sedate. There isn't a lot of running around, hair pulling or teeth gnashing," Meyer said.

Helping Koskinen run the center was his deputy, Janet B. Abrams, and Peter Kind, a retired Army lieutenant general. Like Koskinen, they appear easygoing and congenial, while putting a premium on no-nonsense efficiency. For instance, TV technicians watching "Apocalypse Now" lost their movie privileges when CNN used them as an example of the uneventful day at the command center.

Koskinen had a number of visitors, including Secretary of State Madeleine K. Albright, Environmental Protection Agency Administrator Carol M. Browner and Reps. Stephen Horn (R-Calif.) and Constance A. Morella (R-Md.), co-chair of the House Y2K task force.

Like all large organizations, the command center started to develop its own culture. Cardigan sweaters, featuring the White House Y2K seal, were distributed. They come in four colors, with the inner sanctum wearing white and top aides wearing blue. The public affairs cadre and supporting staff sport teal and black, respectively.

Jack Gribben, Koskinen's press secretary, said the sweaters were "a nice thing for people who are giving up their New Year's weekend."