On this edition of Computer Digest: Face scanning technology, Back-up systems, and wireless laptops.

Airports in the United States are open once again following the September 11 terrorist attacks. Even with increased security efforts, put in place after the attacks, experts are looking for more ways to protect both airline passengers and those on the ground. One promising technique involves what's called facial recognition technology.

"It's computerized technology that allows you to capture faces from live video and match them against a database, a watch list of criminals or terrorists," explains Joseph Atick, chief executive officer of the Visionics Corporation, a New Jersey company that produces identification technologies and systems.

The process begins with a simple camera. "The camera will capture faces in a crowd, in motion, and at a distance," says Mr. Atick. "We convert them into a face print which is the relationship between the landmarks of your face. We'll triangulate those relationships and we'll convert it into a digital code. The digital code gets checked against the codes stored in the database from mug shots, or from surveillance records. If a match happens, then you know you've got the target suspect."

The technology searches for what Mr. Atick describes as "landmarks" on the face, such things as the bridge of the nose, the cheekbones and the sides of the mouth. "It doesn't have to be very clear, as long as you can see about 14 to 20 landmarks in the face," he says. There are about 80 of them. It turns out that by studying the relationship between them you can come up with a code that is unique to you."

Other so-called biometric technologies are also available, including fingerprint imaging and iris scans. "But the problem with them is that no terrorist is going to volunteer their fingerprint to you, or their iris scan to you," notes Mr. Atick. "Facial recognition is much more effective because our intelligence services, in this country, as well as abroad, have been taking pictures of terrorists as they meet someone else."

Vision scanning at airports is one of the methods that government officials are studying to reduce the threat from terrorism.

According to industry analysts, up to 60 percent of a company's critical data is now stored on individual personal computers. Given this trend, many businesses are looking for ways to ensure that their computers run properly and that the information they store remains safe.

Bob Brennan heads Connected Corporation, a Framingham, Massachusetts company that specializes in information protection. "We're a software company and what we've essentially figured out is how to get the information from 10,000 PCs to a single server, efficiently," he says. "From there we can automate the diagnosis of any problem that could go wrong with a PC - whether it be a virus affecting it, or having it lost, stolen or damaged. Then, heal the computer so that it's in a working state, right down to the wallpaper that you have on your PC - the settings, the data itself. We sell it either as a subscription service where our users pay us on a monthly basis, where we capture all of their data, or we sell it as a product license where it is run by our customers in their own environment."

One reason why the services offered by the Connected Corporation, and similar companies, are so popular today is because of the spread of computer viruses. "There is a way of preventing viruses that are known viruses," says Mr. Brennan. "What we are not capable of doing today, as an industry, is preventing viruses that are not yet known."

However, with back-up systems provided by companies like Mr. Brennan's it is still possible to retrieve information that was stored before the virus.

The Toshiba Corporation recently came out with the world's first laptop with built-in antennas. The antennas, which are located in the laptop's lid, will make it possible for the computer to hook up with both long and short-range wireless computer networks, similar to the way cell phones are connected.

Initial users are expected to be business customers. Industry analysts expect that the trend toward wireless laptop networking will expand in the months to come.