Computers are not the only type of electronic devices that may be found in homes and offices. Because of this an entire class of problems exists that creates untold headaches for computer users. Environmental problems for computer users are similar to environmental pollution for human beings and other living things. Electronic pollution is called Electromagnetic Interference, or EMI. EMI is also known as RFI, or Radio Frequency Interference because it lies in the radio frequency ranges of the electromagnetic spectrum.
EMI is unwanted electronic signals that are transmitted or received by an electronic device. Computers can generate EMI that can interfere with the operation of other electronic devices, just as other devices can generate EMI that disrupts your computer system. EMI can be propagated through the air, such as with radio waves and magnetic fields, or through power lines to the power plug of your computer. EMI can propagate into your computer through other signal cables such as USB, serial and printer cables. These signals, whatever the source and however they are propagated, can crash your computer unexpectedly or be the cause of any number of strange and weird symptoms.
Symptoms of EMI can be lockups and hangs, unusual system errors, repeated booting, CRC or storage media errors, or kernel panics. In other words, many of the same symptoms that can be generated by real hardware and software problems can also be caused by EMI problems that are just as real but much harder to find and prove. Many times problems that cannot be traced or explained in any possible way should make you suspicious of EMI.
I have some level of expertise in the area of EMI. While at IBM I was fortunate enough to become the branch office expert on EMI and was able to identify and resolve problems due to EMI that other Customer Engineers were not. I was also able to later work with the division expert on EMI, Mike F., while I was a Course Development Representative in Boca Raton, Florida. Mike and I collaborated to write a handbook and produce a video tape on electrical safety and electromagnetic interference.