For computer users, power outages or brownouts can cause havoc. Reports warn that such events will be more common this summer than usual as the nation's power demand grows to a level approaching supply limits in many areas.

• Today's computerized economy is demanding even fewer interruptions and a much steadier current.

• For example, Pacific Gas and Electric agrees to keep power flowing and prevent voltage surges or dips of 10 percent or more -- but an electric components maker in its region requires that voltages vary as little as 5 percent to avoid system crashes and risk losing materials worth thousands of dollars.

• Worldwide, power disturbances cause more than 17,000 computer disruptions every second -- from annoying frozen cursors to serious destruction of equipment -- according to American Power Conversion, a company which makes backup power systems for computers.

• Rapid, minute changes in voltage represent the ones and zeros that make up digital information and are ultimately translated into a human voice during a telephone call, a calculation during a banking transaction or a dose of radiation during cancer therapy.

Companies that are dependent on reliable power for new technology have nurtured whole industries which provide that reassurance -- from manufacturers of surge suppressers to companies that manufacture backup generators. Experts say that market has grown to $500 billion a year.

Source: Barnaby J. Feder, "Digital Economy's Demand for Steady Power Strains Utilities," New York Times, July 3, 2000.