For years, computer programmers used the code "9999" to indicate that a program had finished its operations and should shut down.

Today is the ninth day of the ninth month of the year '99.

Sounds like the makings of an electronic disaster rivaling the Y2K computer bug as computer systems interpret the date as a command to freeze up.

But technology experts say today's numerical coincidence won't be a big deal. That's largely because most computer systems will represent today as 09/09/99 or 090999. Those two zeros should ensure that computers don't get confused, analysts say.

"This is a big myth," said Mitch Ratcliffe, who runs a year 2000 Web site for publisher Ziff-Davis Inc. "A properly formatted date field will not generate 9999 on September 9 under any circumstances."

Ann Coffou, a managing director with the Giga Information Group in Cambridge, Mass., said none of her clients has discovered any systems that needed to be fixed to handle today's date. The Gartner Group, like Giga a consulting firm, has said it has discovered only a handful of 9/9/99 problems, all of which were confined to old and obscure systems.

Dominion Resources Inc., the parent company of Virginia Power, found a few 9/9/99 issues in "insignificant programs" that produce reports, said Bill Mistr, a vice president who directs the company's Y2K repair efforts. All of the problems have been fixed, he said.

Today isn't the first pre-2000 date to spur fears of computer crashes. Some worried that April 9 (the 99th day of the year), July 1 (the start of many fiscal years) and Aug. 21 (when clocks on the Global Positioning System of satellites reset themselves) would bring severe problems. But in each case, few significant disruptions occurred.

The biggest problem some businesses and government agencies may face today is a totally human goof. Some computer systems, including one used in The Washington Post's newsroom, require users to indicate the day on which they want a file to be automatically deleted. For years, some people have typed in 9/9/99 as a far-off sunset date for files they wanted to save.

At The Post, if a new, later date wasn't typed in, those files were set to become history early this morning.