The UPS and the diesel generator are two means for keeping a server working if there are troubles with the primary power source - an interruption or unreliable current that cannot keep the machine functioning properly, for instance. UPS is an abbreviation for Uninterruptible Power Supply, even though it is frequently called Uninterruptible Power Source too. The UPS is, in simple terms, a powerful battery that is connected to the machine and to the power network all of the time, so in the event of any disturbance, it's already working, which enables the web server to carry on doing the job without losing any information. The diesel generator is an engine that can power up an entire data center. It does take some time to start working and it is the UPS that provides that time. These two power solutions are absolutely essential for any facility or service provider that wants to prevent info loss and hardware damage resulting from an unexpected electric power problem.