RTC

This is implemented in rtc.

The RTC (Real Time Clock) is a hardware clock that is used to provide the current time and date for the system.

The RTC is used as the base time to determine the unix time of the system, and provide this time to the user space.

Beside that, the kernel generally doesn't care about unix, and everything is based on "system boot" time.

The RTC can technically be used as a clock source, such as HPET and TSC, but its accuracy is very low, so for now its not used as such.