UPS is an abbreviation for Uninterruptible Power Supply or Uninterruptible Power Source. This is a battery that is used to power a computer or a web server in order to avoid the loss of information if the main power source fails for some reason or becomes unsafe. A diesel generator is more or less self-explanatory. UPSs and generators are widely-used as a backup in data centers to back up the power supply and to ensure the continuous running of all the machines located there. As the UPS operates all the time, it provides the required power for the servers to remain working until the generator starts and takes over. Using this type of a backup is essential for any data center or service provider that wants to keep their hardware and information intact in case there is a power surge or outage, due to the fact that it provides them with ample time to react until the problem is resolved and the main power supply is restored.