Clocks: The Essential Timers in Multiprogrammed Systems
Clocks in Multiprogrammed Systems
Implementation of Clocks
To implement clocks in a multiprogrammed system, several elements are utilized. The clock within the CPU is typically composed of three main components: 1. Crystal oscillator: This element generates a stable and precise frequency that serves as the basis for the clock's timing mechanism. 2. Counter: The counter keeps track of the oscillator's cycles and increments its value accordingly. 3. Holding register: This component stores the current time value and updates it as per the increments from the counter. Combining these three elements results in the generation of interrupts at specific intervals or durations. These interrupts are essential for coordinating processes, ensuring that each process receives its fair share of CPU time.Battery Backup for Clocks
In order to prevent the loss of time data in case of power loss or system shutdown, clocks are equipped with a powered battery backup. This backup system consists of specialized low-power circuitry similar to that found in digital watches. By utilizing this backup, the system can retain the current time even when not actively powered, ensuring continuity and accuracy in timekeeping. Overall, the implementation of clocks in multiprogrammed systems plays a critical role in maintaining system functionality, coordinating processes, and ensuring accurate timekeeping.Clocks (also called timers) are essential to the operation of any multiprogrammed system. How are clocks implemented?
The clock in the CPU is made of three elements including the following: 1. Crystal oscillator 2. A counter 3. A holding register All these clock elements combined and generate interrupts at known periods or duration. However, the clock has a powered battery back up which is implemented with a form of low-power circuitry similar to that of digital watches. The purpose is to prohibit the current time from being failed when the computer is powered off or shut down.