Mr. Wetmore, 38, is a producer at Prodigy, the on-line computer and Internet service company in White Plains.

"Some of the older patrons still want to rely on the old Dewey Decimal card catalogues, rather than our new on-line computers," said Barbara Wenglin, information librarian at White Plains.

"That's due to all of the problems we had with the on-line computer," Mr. Lewis said.

"We see an enormous opportunity to move revenue out of magazines and into on-line," he said, "particularly in this category: computers."

These networks are programmed to adapt to changes in traffic volume and to failures in any of the thousands of on-line computers.

I often log onto the same already on-line computer without much regard to which access has been entered (because I am a self-taught ungeek) often to my potential embarrassment (or hers).

It has six on-line computers with ready access to a variety of databases and the internet.

The Prodigy Services Company, one of the country's largest on-line computer information services, dismissed an estimated 100 employees yesterday, or nearly 15 percent of its total work force.

With more than 350 on-line computers, ECAM has access to the most advanced communication technologies.

Since 2010 each level of the AAT qualification has a number of modules, each of which culminate in an on-line computer based assessment.