The UPS and the diesel generator are 2 devices for keeping a web server functioning in case there are issues with the primary source - an outage or shaky current which cannot keep the hosting server working correctly, for instance. UPS is an abbreviation for Uninterruptible Power Supply, though it is frequently called Uninterruptible Power Source too. The UPS is, essentially, a powerful battery that is attached to the web server and to the electricity network all of the time, so if there is any blackout, it is already working, that permits the hosting server to continue doing the job without losing any data. The diesel generator is an engine that can power up the entire data center. It does take some time to begin working and it is the UPS that provides that time. These 2 power solutions are fundamental for any facility or hosting company that wants to prevent data loss and hardware damage caused by an unexpected power issue.