What is an Interrupt? Video Lecture | Question Bank for GATE Computer Science Engineering - Computer Science Engineering (CSE)

An interrupt is a signal sent to the processor by an external device or internal program to request its attention. It temporarily suspends the execution of the current program and transfers control to a specific interrupt handler routine. This mechanism allows the processor to handle time-critical events, such as input/output operations, in a timely manner.

When an interrupt is triggered, the processor saves the current state of the program being executed and transfers control to the interrupt handler routine. The handler performs the necessary operations or tasks associated with the interrupt, such as reading data from an input device or writing data to an output device. Once the interrupt handler completes its tasks, the processor resumes the execution of the interrupted program.

There are several types of interrupts, including: 1. Hardware interrupts: These are generated by external devices, such as keyboards, mouse, or network cards, to notify the processor of an event that requires attention. 2. Software interrupts: These are generated by software programs to request specific services from the processor, such as system calls or software-generated exceptions. 3. Maskable interrupts: These interrupts can be disabled or enabled by the processor. The operating system or software programs can control the handling of these interrupts. 4. Non-maskable interrupts: These interrupts cannot be disabled or ignored by the processor. They are typically used for critical events that require immediate attention.

Interrupts are often prioritized to ensure that critical events are handled first. The processor usually assigns a priority level to each interrupt. When multiple interrupts occur simultaneously, the interrupt with the highest priority is serviced first. This allows time-sensitive operations to be processed promptly and ensures efficiency in handling different events.

Interrupts offer several advantages in computer science engineering, including: 1. Responsiveness: Interrupts enable the processor to quickly respond to time-critical events, ensuring timely processing of input/output operations. 2. Efficiency: By suspending the execution of the current program and handling interrupts as they occur, the processor can efficiently handle multiple tasks simultaneously. 3. Modularity: Interrupts allow for modular programming, as different interrupt handler routines can be developed for specific events or devices, making code organization and maintenance easier. 4. Scalability: Interrupt-driven systems can scale well with increasing hardware or software complexity, as the processor can handle a diverse range of events without sacrificing performance. 5. Real-time processing: Interrupts play a crucial role in real-time systems, where meeting strict timing requirements is essential. They enable the processor to respond to time-sensitive events within specific deadlines.