A real time clock alarm
is a feature that can be used to allow a computer
to 'wake up' after shut down to execute tasks every day or on a certain day. It can sometimes be found in the 'Power Management' section of a motherboard
setup. However, newer BIOS setups do not include an RTC alarm option, although it can still be set from within user applications.
In Linux, it can be set or retrieved using /proc/acpi/alarm.