Table of Contents
What is IRQ in computer?
(Interrupt ReQuest) A hardware interrupt on a PC. There are 16 IRQ lines used to signal the CPU that a peripheral event has started or terminated. Except for PCI devices, two devices cannot use the same line. If a new expansion card is preset to the IRQ used by an existing board, one of them must be changed.
How does an IRQ help a computer function?
An IRQ (interrupt request) value is an assigned location where the computer can expect a particular device to interrupt it when the device sends the computer signals about its operation. The signal momentarily interrupts the computer so that it can decide what processing to do next.
What is IRQ assignment?
IRQ numbers are assigned during the boot process to each hardware device that needs one. A device requires an IRQ number if it is able to provide input to the CPU or start an action. The IRQ number is a numeric way to assign the priority that the devices have with the CPU.
How can you view the used IRQ on a system?
Open the Device Manager. Double-click the computer (the first icon listed in Device Manager). You should see numbers 00 – 15; any number that is not listed is an indication that the IRQ is free. If all numbers are listed once or more, this would be an indication that all IRQs are being used.
How does the processor know which device has generated an interrupt How does the processor know which interrupt service routine needs to be executed?
In vectored interrupts, a device requesting an interrupt identifies itself directly by sending a special code to the processor over the bus. This enables the processor to identify the device that generated the interrupt.
What are three IRQs that are commonly used for network adapters?
| IRQ Level | Common Use | Comments |
|---|---|---|
| 3 | COM2 or COM4 | |
| 4 | COM1 or COM3 | |
| 5 | LPT2 | This is usually free as not many people have 2 parallel ports. Sound blaster cards usually use this. |
| 6 | Floppy disk controller |