1. APC Smart UPS daemon This daemon monitors an APC UPS either as master, with the serial cable attached to it, or as a slave, with a network connection to the master. The daemon constantly gathers information from the UPS (battery load, Temperature, workload, etc.) and logs them to a file. It shuts down the system cleanly after a certain period of constant power failure or if the battery load falls below a certain level. From Debian 3.0r0 APT