3.6 Timing ServicesThe kernel provides several different timing services to processes. These services include timers that run in real time and timers that run only while a process is executing.   Real TimeThe system’s time offset since January 1, 1970, Universal Coordinated Time (UTC), also known as the Epoch, is returned by the system call gettimeofday. (협정 세계시) Most modern processors (includin..

3.4 Clock InterruptsThe system is driven by a clock that interrupts at regular intervals. Each interrupt is referred to as a tick. On the PC, the clock ticks 1000 times per second. At each tick, the system updates the current time of day as well as user-process and system timers.  Handling 1000 interrupts per second can be time consuming. To reduce the interrupt load, the kernel computes the num..