The power supply to a computer system constantly receives different forms of electrical changes. The most widely known is the power "spike" which is usually associated with lightning striking a power line. Another more common but less known event is known as a "brownout". A brownout is when the voltage level in your household electrical system drops below normal. This occurs quite often and can damage a computer system over time.

     Another common event is when the household power supply fails all together. If you are in the habit of hitting [ALT]+F+S when working in Windows applications, you may not be as vulnerable as a user who does not save their working documents on a regular basis. The best cure for these events is to buy a UPS. A UPS is an Uninteruptable Power Suppy. A UPS is simply a box with a battery which will supply the computer with limited power in the event of a power outage. This time frame allows you to save your work and properly shutdown a computer system. I bought a UPS because the Linux OS is best maintained when shutdown or restarted properly (unmounting filesystems).

Surge Protection

     A computer system should use a surge protector. There is a wide range of surge protectors available most of which are differentiated by the amount of Joules which it will protect from and the speed in which it "clamps" or how fast it's protection is activated during a surge. You should note that if you bought an UPS, it has a high-end surge protection system built into the box. This makes the UPS a good up-front purchase.

     When implementing surge protection for your computer, you should also provide a mechanism for protecting the phone line connected to your modem. A phone line surge is just as possible and is just as good a route into a computer system as the household power supply. Better surge protection units include phone line protection, Radio Shack sells small inline protectors, and UPS systems provide high-end built-in protection.

     When analyzing my own home network, I realized that a 486dx system was using a direct connection to my phone line. I was not really concerned because the computer was so old. After thinking more on the situation, I realized that the spike could travel through phone line to the computer and across the network into my primary computer. With all the protection implemented on the main computer, it was just as vulnerable as the unprotected 486dx.

Uninteruptable Power Supply (UPS)