What are they?
Power failures, also known as blackouts, are the easiest power problem to diagnose. If the lights go out, chance are there has been a power failure. Any temporary, or not so temporary, interruption in the flow of electricity will result in a power failure which can cause hardware damage and data loss.
Where do they come from?
Violent weather is the first thing that comes to mind, but there are any number of other causes. Overburdened power grids, car accidents that bring down power lines, lightning strikes, and human error are all likely sources.
What can they do?
Power failures are more than simply inconvenient and annoying. They can cause computer users to lose hours of work when systems shut down without warning. Power failures can even damage hard drives resulting in loss of all data on a system. Consider the fact that a single power outage on a high traffic network can stall hundreds of users, and the seriousness of power failures becomes evident. Even worse, when the power returns, it often brings after-blackout spikes and surges to cause even more damage.
What can be done?
Computer users should consider a UPS system to protect their systems. These systems monitor line levels and switch over to battery power when utility power fails.