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Internet Search Engines

Looking at the Web
When most people talk about Internet search engines, they really mean World Wide Web search engines. Before the Web became the most visible part of the Internet, there were already search engines in place to help people find information on the Net. Programs with names like "gopher" and "Archie" kept indexes of files stored on servers connected to the Internet, and dramatically reduced the amount of time required to find programs and documents.

In the late 1980s, getting serious value from the Internet meant knowing how to use gopher, Archie, Veronica and the rest. Today, most Internet users limit their searches to the Web, so we'll limit this article to search engines that focus on the contents of Web pages.

An Itsy-Bitsy Beginning
Before a search engine can tell you where a file or document is, it must be found. To find information on the hundreds of millions of Web pages that exist, a search engine employs special software robots, called spiders, to build lists of the words found on Web sites. When a spider is building its lists, the process is called Web crawling. (There are some disadvantages to calling part of the Internet the World Wide Web -- a large set of arachnid-centric names for tools is one of them.)

In order to build and maintain a useful list of words, a search engine's spiders have to look at a lot of pages. How does any spider start its travels over the Web? The usual starting points are lists of heavily used servers and very popular pages. The spider will begin with a popular site, indexing...............

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VPNs Made Easy

Physicians at Catholic Health System in Buffalo, N.Y., want access to medical information and images. Managers at Perry Manufacturing Co. in Mount Airy, N.C., need remote access to e-mail and applications running on an AS/400. At these businesses and elsewhere, users are becoming increasingly reliant on remote access to business applications and data. Yet even in the era of the Internet, there has been no easy and secure way to provide remote access to the data and applications users need. Dial-up connections, terminal emulation tools, Internet portals and traditional virtual private networks (VPN) can do some of the job, but each has its limitations.

"We had an old dial-up product to reach the AS/400, but no e-mail," recalls Howard Ward, Perry's director of information systems. The company had Cisco's Easy VPN for e-mail but found it to be too slow, he adds.

Catholic Health wanted to give physicians remote access to patient information and medical test results. Its first attempt�sending medical information and images via fax�proved cumbersome. Then it deployed a VPN based on the IPsec protocol. That provided session encryption and authentication and enabled network-level access to resources, but it also proved problematic. "Some physicians still use our VPN, but there are real support issues. You need to configure software on each client. What we wanted was an application-level gateway of some sort," explains Douglas Torre, director of networking...............

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Life and Evolution in Computers

Computers and Life
Can we build computers that are intelligent and alive? This question has been on the minds of computer scientists since the dawn of the computer age and remains a most compelling line of inquiry. Some would argue that the question makes sense only if we put scare quotes around intelligent" and alive," since we're talking about computers, after all, not biological organisms. My own view is that the answer is unequivocally yes, no scare quotes or other punctuation needed, but that to get there our notions of life, intelligence, and computation will have to be deepened considerably.

You can ask ten biologists what are the ten (or 20 or 100) key requisites for life and you'll get a di�erent list each time. But most are likely to include autonomy, metabolism, self- reproduction, survival instinct, and evolution and adaptation. As a start, can we understand these processes mechanistically and...........

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