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Interrupt Request

Definition

An Interrupt Request, often abbreviated as IRQ, is a signal sent from a device or software to a processor in a computer to request its attention. It is a way of interrupting the processor’s current activity, prompting it to pause and address the interrupting task before resuming the original operation. This process allows multiple duties to be managed and prioritized in an efficient manner.

Phonetic

The phonetic transcription of the keyword “Interrupt Request” is /ˌɪntəˈrʌpt rɪˈkwɛst/.

Key Takeaways

  1. Interrupt Request (IRQ) is a signal sent to the processor from a hardware device or software program indicating an event that needs immediate attention.
  2. Each IRQ has a unique priority level to prevent multiple devices from interrupting at the same time, ensuring that all signals are handled effectively without conflict.
  3. Early computers only had a limited number of IRQ lines. However, modern computers have advanced systems that can handle multiple devices using the same IRQ, making them more efficient and flexible.

Importance

Interrupt Request (IRQ) is an essential aspect of computer technology because it facilitates communication between hardware and software in computer systems. IRQs allow various devices to request attention from the processor, enabling efficient and simultaneous operations. When a hardware component needs the processor’s attention, it sends an interrupt request. The processor, in turn, interrupts its current activity to address the request, ensuring tasks such as printing documents, saving files, or loading applications are effectively processed. This mechanism is crucial for multitasking, system performance, and overall smooth functioning of a computer system.

Explanation

An Interrupt Request, often abbreviated as IRQ, is a crucial aspect of computer architecture that ensures smooth functioning by effectively allocating processor time among multiple processes. Its primary purpose is to handle requests or service tasks that need urgent attention. The entire mechanism of an IRQ allows the central processing unit (CPU) to be interrupted by external devices or software when they are in need of processor’s capability. By doing this, it ensures that urgent tasks are expedited and performed immediately rather than waiting in queue. For instance, when you press a key on your keyboard or when your printer has finished printing, an interrupt signal is sent to the CPU. This prompts the CPU to temporarily pause its current task, and direct its resources to address the interrupting issue. This mechanism optimizes multi-tasking, as the CPU can effectively manage requests from multiple sources, increasing overall system performance and managing real-time operations efficiently. Therefore, Interrupt Requests are crucial in coordinating tasks and creating harmony between hardware and software, paving the way for an efficient multi-tasking environment.

Examples

1. Computer Hardware Communication: This is perhaps the most common and clear cut illustration of the interrupt request concept. For example, when you press a key on your computer’s keyboard, it sends an interrupt request to the processor. The processor stops its current task and alerts the operating system, which checks what key was pressed. Once this process is done, the processor then goes back to its previous task.2. Mouse Movement or Click: Another example is when you move or click the mouse on your computer. The mouse will also send an interrupt request to the processor. This ensures that the cursor on the screen is in sync with your mouse movements or clicks.3. Network Interface Card (NIC): When the NIC receives data packets over the network, an interrupt request is sent to the processor to indicate that the data packets have arrived and need to be processed. The processor will stop its current work, process the data packet, and then the processor can resume its previous work, guaranteeing the user’s smooth internet experience.

Frequently Asked Questions(FAQ)

**Q1: What is an Interrupt Request (IRQ)?**A1: An Interrupt Request (IRQ) is a hardware signal sent over a line to the processor that alerts it to stop ongoing tasks and attend to an urgent task. The processor takes notice of this interruption and performs the new task before returning to its previous task.**Q2: What is the main purpose of an Interrupt Request?**A2: The main purpose of an Interrupt Request is to alert the processor about high-priority tasks that need immediate attention, ensuring that real-time events are processed efficiently.**Q3: What are some examples of devices that use IRQs?**A3: Various hardware devices utilize IRQs to communicate with the Central Processing Unit (CPU). Typical examples include the keyboard, mouse, sound card, and hard disk.**Q4: Are there different types of Interrupt Requests?**A4: Yes, there are software interrupts, synchronous interrupts, and hardware interrupts. A software interrupt is usually an interrupt generated within a processor by executing an instruction. Synchronous interrupts are generated by I/O devices that send an interrupt request when they are ready to accept or send data. Hardware interrupts are generated by external hardware devices to communicate with the processor.**Q5: Can multiple devices share the same IRQ?**A5: In modern systems, IRQ sharing is possible thanks to advanced programmable interrupt controllers. However, this was not feasible in older systems, and IRQ conflicts between two devices could lead to system instability or crashes.**Q6: How does the processor handle multiple interrupt requests at the same time?**A6: The processor handles multiple interrupt requests through a process known as ‘interrupt prioritizing’. This means that each interrupt type is assigned a priority level. If multiple interrupts occur simultaneously, the processor will handle the highest priority interrupt first. **Q7: Can a user modify or change the IRQ settings?**A7: Yes, a user can change the IRQ settings, but it is not recommended unless they have advanced technical knowledge. Improper changes to the IRQ settings could cause significant system issues. Changes are typically made through the device’s BIOS setup menu or through the operating system’s Device Manager.

Related Tech Terms

  • IRQ Line
  • Programmable Interrupt Controller
  • Interrupt Handler
  • Interrupt Vector Table
  • Direct Memory Access

Sources for More Information

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