John Koskinen, President Clinton's top Y2K troubleshooter, told reporters: "By sometime on Tuesday, we'll have a pretty good idea of where we are in the United States."
So far, fallout from the Y2K bug has been so slight that a Cuban state newspaper suggested the whole thing was a capitalist plot to sell more computers. But both Koskinen and Bill Gates, chairman and CEO of Microsoft Corp. (Nasdaq: MSFT), said there would be more to come.
"In the months ahead, you're going to hear about billing systems or tax-related software that's going to get screwed up," Gates said Saturday night on CNN's "Larry King Live."
"It's not going to be catastrophic, I don't think in any case, but there's going to be lots of snafus," said Gates, whose Windows operating system is the face of computing to most users.
Koskinen concurred. Though major disruptions have been avoided so far, Y2K glitches that may require "work-arounds" are bound to start popping up, he said.
Still, Koskinen said he hadn't spoken to President Clinton during the weekend. Instead, he brought Vice President Al Gore up to date on Friday and Saturday, as scheduled.
There were glitches, though. The Y2K bug temporarily stopped the supply of warm water and the operation of Korean-style hot air "ondol" floor heaters at 902 households at a high-rise apartment complex on the outskirts of Seoul midnight Saturday, South Korean officials said.
The trouble in the province of Kyonggi is regarded as the world's first large-scale disturbance to many people's lives and is believed to have been caused by a Y2K-related malfunction of the complex's computer control system.
Engineers conducted emergency repairs, and the floor heater was restarted Saturday evening. The warm-water supply was also restarted Sunday morning.
The warm-water supply and floor heaters were functioning normally by Sunday evening as the computer control system was replaced with a Y2K-compatible model, the officials said.
The computer system, which was installed about a decade ago, was not updated to be Y2K-compliant.
Several nuclear power plants in the United States had minor glitches, but none interrupted power supplies.
Problems with heart monitoring equipment in Swedish hospitals were one of the few signs of the millennium bug biting elsewhere, as computer experts prepared for the reopening of major financial markets and businesses.
Electrocardiograph machines at the main hospital in Uppsala, north of Stockholm, and at regional hospitals in Karlstad and Linkoping stopped working, although a spokeswoman told the Svenska Dagbladet that patients' safety was not threatened.
Newfound wealth: $6 million
In Germany, a salesman who logged into his home banking computer account found a malfunction had inflated his wealth to more than 12 million marks (US$6.2 million) -- as of Dec. 30, 1899. But it was unclear whether this was due to the millennium bug.
In the United States, a video store fined a customer more than $90,000 for returning a video 100 years late. The customer got a recalculated late charge -- and a free rental -- from the amused store owner.
The Pentagon said Saturday that a failure in a ground-based system prevented officials from handling information from some U.S. intelligence satellites for a few hours on Friday night. France said one of its defense satellite systems lost the ability to detect equipment failures.
A computer linked to radiation monitoring systems seized up at a Japanese nuclear power plant, and door locks sealing off sensitive areas refused to open at nuclear plants in Arkansas and Spain.
Overall, though, such problems were few and far between. Across the world, markets, telecommunications and other infrastructure officials reported all systems were go.
Even countries where chaos and disruption can be daily ordeals reported clear sailing.
Venezuela, engulfed by deadly mudslides and floods last month, said its oil industry operations were working normally. So were oil operations in Nigeria, Africa's most populous nation, where experts feared its chaotic infrastructure would buckle.
The small stock exchanges of Egypt and Bangladesh opened today without any problems, and in early trading, the Chicago Mercantile Exchange reported no problems.
The glitches came after a smooth shift-over from 1999 to 2000, which left relieved U.S. officials cautiously optimistic.
"It's been a good Y2K day for the world ... but it's far too early to declare victory," said U.S. Energy Secretary Bill Richardson on Saturday.
Koskinen said it would take an extra day or two after that "before we can start to close the books on Y2K for the world." But, he said that in the short term he was "pleasantly surprised" at the lack of disruptions from the computer bug as of early Saturday morning in the United States.
Of continuing concern were possible hidden Y2K glitches that could foul up management systems and gradually erode performance as businesses reopen this week, officials said.
Transportation Secretary Rodney Slater reported a smooth transition for U.S. aviation, railroads, and maritime traffic and pipeline systems after midnight Greenwich Mean Time (GMT), the standard on which transportation operates.
A few confused clocks
Electric industry officials said a few confused clocks were the only problems reported in the North American electricity grid.
"Three clocks timed to run on Greenwich Mean Time had a problem ... but this had no effect on power supply or power operations," said Jerry Cauley, a spokesman for the North American Electric Reliability Council (NERC).
Energy Secretary Richardson said nuclear facilities in Russia and the rest of the world had successfully crossed into the new year with no reported computer glitches.
Experts had expected to see problems surface in parts of Asia and in Russia, but as the dateline rolled across the globe, there were no significant reports of incidents related to the Y2K computer bug.
"Everything is OK. Everything is as it was. There are no failures, everything is working," an officer at the Russian Strategic Rocket Forces' main command bunker told Reuters by telephone.
The Russian reports followed a string of nonevents in New Zealand, Australia, Japan, India and other nations.
Too much hype?
Some ZDNN readers were quick to blame the media for overhyping the Y2K threat.
"This situation would not have occurred if the stupid media would have stopped the over-hype of the situation and just report it as any other news story," wrote Dave C from Pittsburgh, in a ZDNN story TalkBack. "ZDnet is just as bad at the over-hype also with at least one 'what could happen' story a day on their site."
But others said there were many Y2K bugs -- they just got caught in time. "Y2K bug testing within my corporation did reveal major bugs within older legacy systems that relate to the factory floor," wrote Jeff F. "We simulated the date rollover and some of our systems died on the spot. Y2K was not hype, and the efforts of IT professionals to eradicate/alleviate the disaster is appreciated, at least within my company."
Material from Reuters was used in this story.