The UPS and the diesel generator are two instruments for keeping a web server operational in case there are problems with the main power supply - a disruption or unstable current that can't keep the server functional, for example. UPS is an abbreviation for Uninterruptible Power Supply, even though it is oftentimes called Uninterruptible Power Source too. The UPS is, in essence, a powerful battery that's attached to the machine and to the electricity network all of the time, so in the event of any disruption, it is already operating, that permits the server to keep on operating without losing any info. The diesel generator is an engine which will power up the whole data center. It does take some time to start working and it's the UPS which gives it this time. Those 2 power solutions are a requirement for any facility or service provider that wants to stop information loss and hardware damage as a result of an unexpected electric power issue.