CRASHES POINT TO NETWORKS' FRAGILITY.

Byline: The Boston Globe

Two major breakdowns on the Internet in the past few days have shown how unreliable computer networks can be despite having become a heavily used mode of communication.

A single faulty line of code in a computer program crashed the nation's biggest Internet direct-access network late Tuesday. Netcom On-Line Communications Services Inc., which serves 400,000 homes and businesses, was out of commission from about 4 p.m. PST on Tuesday until about 5 a.m. Wednesday. ``We had so many calls to customer service it blew out our phone system,'' said David Garrison, Netcom's chairman and chief executive.

Meanwhile, the 5.5 million users of America Online, the largest commercial on-line service, were unable to transmit electronic mail for an hour Wednesday afternoon. Other AOL services were unaffected.

Tom Pincince, a senior analyst for Forrester Research in Cambridge, notes that the Netcom and AOL incidents are just large-scale versions of the reliability problems that are common on the Internet.

According to spokeswoman Pam McGraw, AOL's electronic mail system was sluggish throughout the day. So AOL engineers removed and reinstalled the mail software, leading to a one-hour shutdown of the system.