interrupttien

An interrupt, in computer science, is a signal to the processor, generated by hardware or software, indicating an event that needs immediate attention. When an interrupt occurs, the processor suspends its current task, saves its state, and then executes a special routine called an interrupt handler or interrupt service routine (ISR). This handler addresses the cause of the interrupt. Once the handler completes its execution, the processor restores its saved state and resumes the interrupted task.

Interrupts are crucial for efficient system operation. They allow the processor to multitask, responding to events like keyboard input, mouse movements, network packet arrivals, or disk drive operations without constantly polling for these events. Polling would be inefficient as it would require the processor to repeatedly check the status of devices, wasting valuable processing time.

There are two main types of interrupts: hardware interrupts and software interrupts. Hardware interrupts are generated by external devices via an interrupt controller. Software interrupts, on the other hand, are generated by executing specific instructions within a program. These are often used for system calls, allowing user programs to request services from the operating system.

The interrupt vector table (IVT) is a data structure used by the processor to store the addresses of interrupt handlers. When an interrupt occurs, the processor uses an interrupt number to look up the corresponding handler's address in the IVT and then jumps to that address to execute the ISR. This mechanism ensures that the correct handler is invoked for each type of interrupt. Managing interrupts effectively is a key aspect of operating system design and real-time systems.