Internal interruptions are produced by convinced events which come during the execution of a program.
These types of interruptions are handled on their totality by the hardware and it is not feasible to modify them.
A clear instance of this type of interruptions is the one which recognizes the counter of the computer internal clock; the hardware makes the call to this interruption quite a few times during a second so as to maintain the time to date.
yet though we cannot directly manage this interruption, as we cannot control the time dating by means of software, it is possible to use its effects on the computer to our profit, for instance to create a "virtual clock" dated continuously thanks to the clock''s internal counter. We only have to write a program which studies the actual value of the counter and to translate it into a comprehensible format for the user.