Windows XP / Networking

---

Avoiding Zapped Computers

You know that electricity is dangerous, so you probably avoid sticking your fingers into live light-bulb sockets and electrical outlets. Your computers may not have fingers, but they Are sensitive to electricity, too, and it Is up to you to protect them from a variety of electrical dangers.

Protecting against telephone line surges

Large networks destroyed during a lightning storm, and in each case, the surge came through the telephone lines, not the electrical lines. This is what happens: Lightning hits the telephone line, the surge comes through the telephone jack in the wall, it travels along the telephone cable from the wall to the modem, it travels from the modem to the computer's motherboard, it travels from the motherboard to the rest of the computer parts, including the network interface card (NIC), the NIC sends the surge out to the network cable, the cable sends the surge back to every NIC on the network, and each NIC sends the surge to its computer's motherboard. Every computer on the network is fried.

In most communities, the power company installs lightning arresters, which help diffuse the effects of a direct lightning hit on the electric lines. However, no telephone company that protects its phone lines against lightning. When a lightning storm is close, unplug your modem telephone cable at the wall jack and then unplug the computers.

If your telephone company has fiber optic lines (rather unlikely), you don't have to worry as much about lightning hits because those lines don't conduct electricity. Ask your telephone company what types of lines are connected to your home.

Protecting Against Electrical Surges

An electrical surge is a sudden spate of very high voltage that travels from the electric lines to your house and ultimately to your computer. Computers are particularly sensitive to surges, and a real surge can fry your computer. The chips burn up, and your computer becomes a doorstop.

Most of the time, surges occur as a result of a lightning strike, but the danger of a surge also exists if there is a brief blackout followed by a return of electricity. During the return of power, the voltage can spike.

You can safeguard against spikes by plugging your computer into a surge protector. The surge protectors that are commonly used look like electrical power strips, usually with four or five outlets. Read the specifications before you buy a surge protector to make sure that it is rated for real surge protection. (Voltage can rise by 10 volts or hundreds of volts, so make sure the surge protector you buy can handle these extreme surges.)

Surge protectors work by committing suicide to protect your computer. They absorb the surge so it does not travel to your equipment. (Some surge protectors have reset buttons that bring the strip back to life.)

If a power surge hits any piece of equipment that is attached to your computer by cable, the surge can travel to your computer. Therefore, plugging the computer into the surge protector is not quite enough; you also have to use the surge protector to power the accessories that are connected to your computer.

Because any surge received by a single computer can travel over the network cable to the other computers on your network, make sure that all the following equipment for each of your computers is plugged into surge protectors:

• External removable drives
• External modems
• Monitors
• Speakers

Never plug a printer into the same surge protector that your computer is already plugged into. (In fact, if you have a laser printer, you should never plug it into the same circuit as your computer.)

Protecting against power loss

When you are running Windows, you can't just turn off your computer when you don't want to use it anymore. You must initiate a shutdown procedure using the Shut Down command on the Start menu. Otherwise, you may have a problem restarting your computer, or you may run into mysterious problems when you try to use software and Windows features after a power failure.

The electric company does not know and does not care about the need for an orderly shutdown, and if the folks there did know or care, they could not do much to warn you about a power failure, giving you time to use the Shut Down command.

You can keep your computers running long enough to complete an orderly shutdown of all your software and the operating system if you have an uninterruptible power supply (UPS). A UPS is a mega-battery that you plug into the wall, and you then use the UPS outlets to connect your computer and monitor. If your power fails, your computer draws power from the battery, giving you enough time to shut down everything.

UPS units come in a variety of power configurations (measured in watts). Some have line conditioning in addition to the battery feature. Some have software that performs the orderly shutdown for you. (The UPS unit connects to your computer through a serial port to communicate.) This is a nice feature if your power dies while you are away from the computer. The cost ranges from about $80 to several hundred dollars, depending on the wattage and the features you want. The best-known UPS units are made by APC. They are available anywhere computer peripherals are sold.

Preventing static electricity damage

Static electricity is responsible for more damaged computers than most people realize. One day, when some hardware component mysteriously dies, you may not realize that you zapped it yourself.

Static electricity charges that zap your computer come from you. You pick up static electricity, carry it with you, and pass it along when you touch any part of the computer. Usually, the keyboard receives your first touch, and even though it is connected to your computer, it does not always pass the electricity along to the computer.

However, if you touch the monitor or the computer box, you can pass a serious or fatal amount of electricity to the motherboard (fatal to the computer, not to you) or to any component in your computer (including chips).

You must discharge the electricity from your body before you touch the computer. Touch anything metal (except an electric appliance such as a computer or a lamp). A filing cabinet is good if one is handy. If nothing metal is within reach, attach a metal bar to the desk or table that your computer sits on. Computers and carpeting create the ideal atmosphere for zapping. New carpeting is really dangerous, followed by carpeting with a thick pile. If you can't pull up the carpeting, go to an office supply store and buy one of those big plastic mats that goes under the desk and your chair. If you don't, each time you move your feet, you will collect static electricity and eventually pass it to the computer.

Protecting against lightning hits

If lightning hits your power lines or your house, your surge protector may not be able to protect your equipment against the resulting surge. Thousands or tens of thousands of volts sometimes more - result from a lightning strike. A surge protector can provide only so much protection, and a direct lightning hit exceeds that limit.

The only protection against lightning strikes is to unplug your computers and all your computer equipment. Stop working. Then walk around the house and unplug other equipment with chips that could fry during a lightning storm (like your microwave oven, VCR, and so on).

Understanding and fixing low-voltage problems

Sometimes, when everyone in town is using electrical gadgets at the same time, an area's all-around voltage drops. This is called a brownout. Computers especially their hard drives and motherboards - are extremely sensitive to brownouts.

Well before you see the lights flicker, your hard drive can react to a brownout. Most of the time, that reaction destroys the part of the drive that is being accessed, and the result is that your drive develops bad spots - parts of the drive that can't be written to or read from. You can mark the bad spots to prevent the operating system from using those spots to hold data, but if the spots that go bad already have data on them, that data goes bad, too.

You can prevent most of the problems associated with bad spots caused by brownouts, and you can overcome those problems that you can't prevent by purchasing a voltage regulator. This clever device constantly measures the voltage coming out of the wall.

If you purchase a voltage regulator in addition to a UPS unit, plug the voltage regulator into the wall. If you are also using a surge protector, the surge protector is always plugged into the wall, with any other devices plugged into the surge protector. Here are some of the causes of low voltage, along with possible fixes:

• An appliance that is a voltage pig (for example, air conditioning and electric heating systems) kicks on, disrupting voltage throughout the house. Plug your computer into a voltage regulator.
• Too many appliances are plugged into the same circuit as your computer. This is something you can fix. Move stuff around, buy some very long heavy-duty extension cords to get to an outlet on another circuit, or call an electrician and get more outlets connected to empty breakers.
• Your laser printer (or powerful ink jet color printer) is plugged into the same circuit as your computer. You should not plug these printers into the same circuit as your computer. If you have no choice, plug the computer into a voltage regulator. Do not plug the printer into the voltage regulator.
• The electric company is sending low voltage into your home. Sometimes, the electric company just can't keep up with demand, and it delivers lower-than-normal voltage to your home. When the voltage really drops, the electric company calls it a brownout. This frequently occurs during very hot weather, when air conditioners in your area are running constantly and working hard. The problem also occurs around 9:00 in the morning, on weekdays, as businesses all over town are turning on copy machines and laser printers, and elevators are constantly going up and down.