There are two many reasons that clocks are very essential to the operation of any multiprogrammed system.
Clock maintain the time of day and prevent one process from monopolizing the central processing unit among other things.
The clock software can take the form of a device driver, even though a clock is neither a block device, nor a character device like disk and mouse.
Now let's talk about the clock software or clock driver.
The work of clock driver varies among OSs. But the clock driver's work generally include the following: