Interruptsignal

Interruptsignal refers to a mechanism by which an external event, hardware device, or software instruction can temporarily interrupt the normal sequence of a computer’s execution to request attention from the processor. The purpose is to allow timely handling of asynchronous events such as I/O, timers, or exceptional conditions without the need for the CPU to constantly poll peripherals.

There are two main types: hardware interrupts and software interrupts. Hardware interrupts are generated by devices and often managed through interrupt controllers. They can be further classified by masking (maskable) and non-maskable interrupts (NMI). They may also be edge-triggered or level-triggered, affecting how the interrupt line signals an event. Software interrupts are initiated by running software, for example through an instruction that triggers a trap or system call, or by signals in an operating system.

When an interrupt occurs, the processor typically saves its current state, switches to a privileged mode, and transfers control to a corresponding interrupt handler or service routine. This handler performs the necessary work, such as reading input from a device or acknowledging an event, and then returns control to the interrupted task, restoring the previous state. The time between the interrupt request and the start of the handler is called interrupt latency, influenced by hardware design and software constraints.

Modern computer systems use advanced interrupt architectures, such as programmable interrupt controllers and IO APICs, to route and prioritize many interrupt streams across multiple CPUs. In operating systems, signals are a related concept used to notify processes of asynchronous events. Interruptsignals are essential for responsive I/O, real-time processing, and efficient multitasking.