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Service Providers

In truth, the Internet was not designed to link computers but rather to tie together computer networks. As its name implies, the Internet allows data to flow between networks. Even if you only have a single computer, when you connect with the Internet, you must run a network protocol the same as if you had slung miles of Ethernet cable through your home and office. Whether you like it or not, you end up tangled in the web of networking when you connect to the Internet.

The ISP actually operates as a message forwarder. At the ISP, your message gets combined with those from other computers and sent through a higher-speed connection (at least you should hope it is a high-speed connection) to yet another concentrator that eventually sends your packet to one of five regional centers (located in New York, Chicago, San Francisco, Los Angeles, and Maryland). There, the major Internet carriers exchange signals, routing the packets from your modem to the carrier that will haul them to their destination based on their Internet address.

Performance Limits

Linking to the Internet requires both hardware and software. The hardware runs a wide gamut. Most people connect through standard telephone lines using a modem.

Okay, so your Internet access through your modem or digital connection isn't as fast as you'd like. Welcome to the club. As the Duchess of Windsor never said, "You can never be too rich or thin or have an Interconnection that's fast enough." Everyone would like Web pages to download instantly. Barring that, they'd like them to load in a few seconds. Barring that, they'd just like them to load before the next Ice Age.

The most tempting way to increase your Internet speed is to update your modem—move from dial-up to a broadband service such as DSL, cable, or satellite. Once you do, you may discover the dirty secret of the Internet: You're working on the wrong bottleneck. You may have a high-speed connection, but the server you want to download pages from may be someone's ten-year-old computer hogtied by a similar-vintage 9600bps modem. Or a server with heady-duty equipment may be overwhelmed by more requests than it can handle. Remember, your packets may get slowed anywhere along their way through the Web.

You can easily check your Internet bottleneck and see what you can do about it. Pick a large file and download it at your normal online time. Then, pry yourself out of bed early and try downloading the same file at 6 a.m. EST or earlier when Internet traffic is likely to be low. If you notice an appreciable difference in response and download times, a faster modem won't likely make your online sessions substantially speedier. The constraints aren't in your computer but in the server and network itself.

Another way to check is with one of the many services designed for checking DSL speed. To find one, simply perform a Web search for "DSL speed test." One choice is www.dslreports.com.


As originally conceived, the Internet is not just a means for moving messages between computers. It was designed as a link between computer systems that allowed scientists to share machines. One researcher in Boston could, for example, run programs on a computer system in San Francisco. Commands for computer systems move across wires just as easily as words and images. To the computer and the Internet, they are all just data.

Much of the expense businesses put into connecting to the Internet involves undoing the work of the original Internet creators. The first thing they install is a firewall, which blocks outsiders from taking control of the business's internal computer network. They must remain constantly vigilant that some creative soul doesn't discover yet another flaw in the security systems built into the Internet itself.

Can someone break into your computer through the Internet? It's certainly possible. Truth be told, however, rummaging through someone's computer is about as interesting as burrowing into his sock drawer. Moreover, the number of computers out there makes it statistically unlikely any given errant James Bond will commandeer your computer, particularly when there's stuff much more interesting (and challenging to break into) such as the networks of multibillion dollar companies, colleges, government agencies, and the military.

The one weakness to this argument is that it assumes whoever would break into your computer uses a degree of intelligence. Even a dull, uninteresting computer loaded with naught but a two-edition-old copy of Office can be the target of the computer terrorist. Generally, someone whose thinking process got stalled on issues of morality, the computer terrorist doesn't target you as much as the rest of the world that causes him so much frustration or boredom. His digital equivalent of a bomb is the computer virus.

A computer virus is program code added to your computer without your permission. The name, as a metaphor for human disease, is apt. As with a human virus, a computer virus cannot reproduce by itself—it takes command of your computer and uses its resources to duplicate itself. Computer viruses are contagious in that they can be passed along from one machine to another. And computer viruses vary in their effects, from deadly (wiping out the entire contents of your hard disk) to trivial (posting a message on your screen). But computer viruses are nothing more than digital code, and they are machine specific. Neither you nor your toaster nor your PDA can catch a computer virus from your computer.

Most computer viruses latch onto your computer and lie in wait. When a specific event occurs—for example, a key date—they swing into action, performing whatever dreadful act their designers got a chuckle from. To continue infecting other computers, they also clone themselves and copy themselves to whatever disks you use in your computer. In general, viruses add their code to another program in your computer. They can't do anything until the program they attach themselves to begins running. Virus writers like to attach their viruses to parts of the operating system so that the code will load every time you run your computer. Because antivirus programs and operating system now readily detect such viruses, the virus terrorists have developed other tactics. One of the latest is the macro-virus, which runs as a macro to a program. In effect, the virus is written in a higher-level language that escapes detection by the antivirus software.

Viruses get into your computer because you let them. They come through any connection your computer has with the outside world, including floppy disks and going online. Browsing Web pages ordinarily won't put you at risk because HTTP doesn't pass along executable programs. Plug-ins may, however. Whenever you download a file, you run a risk of bringing a virus with it. Software and drivers that you download are the most likely carriers. Most Webmasters do their best to ensure that they don't pass along viruses. However, you should always be wary when you download a program from a less reputable site. The same warning applies to e-mail from unknown senders.

There is no such thing as a sub-band or sub-carrier virus that sneaks into your computer through a "sub-band" of your modem's transmissions. Even were it possible to fiddle with the operation of a modem and add a new, invisible modulation to it, the information encoded on it could never get to your computer. Every byte from an analog modem must go through the UART in the modem or serial port, then be read by your computer's microprocessor. The modem has no facility to link a sideband signal (even if there were such a thing) to that data stream.

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