The UPS and the diesel generator are 2 devices for keeping a web server functioning if there are issues with the primary source - an interruption or shaky current which cannot keep the hosting server working correctly, for example. UPS is an abbreviation for Uninterruptible Power Supply, even though it is oftentimes called Uninterruptible Power Source also. The UPS is, essentially, a highly effective battery that's connected to the server and to the electricity network at all times, so in case there is any blackout, it's already operating, which enables the hosting server to continue doing the job without losing any information. The diesel generator is an engine that can power up the entire data center. It does take some time to start working and it's the UPS that gives it this time. These two power solutions are absolutely essential for any facility or provider that wants to avoid info loss and hardware damage caused by an unexpected electric power issue.