The use of atomic weapons at the end of World War 2 fostered fears about their potential use during the Cold War years.
Interrupts and signals are low-level mechanisms that can alter the flow of control in a way similar to a subroutine, but usually occur as a response to some external stimulus or event (that can occur asynchronously), rather than execution of an 'in-line' control flow statement.
Controlled Variable â The controlled variable is a process parameter being controlled. In the example here, water level in the tank is the controlled variable, but it can be any process you wish to control. Controlling this variable is the primary function of process control.