2 ms·
It was an essential part of 90's PC configuration hell. IRQ is short for "Interrupt Request" and each peripheral or device that needs to interrupt the CPU for
by hn8305823 3y ago
It was an essential part of 90's PC configuration hell.
IRQ is short for "Interrupt Request" and each peripheral or device that needs to interrupt the CPU for time-sensitive processing needed to be assigned one. There were only 16 of them with several hard coded for certain things like RTC. Since each serial port, parallel port, floppy controller, HDD controller, video card, sound card, etc needed an IRQ assignment it was not unusual to run out of free ones and resort to overloading one or more. This was less than ideal as now multiple drivers are waking up unnecessarily for the same IRQ.
Originally these were set with physical jumpers on the motherboard and expansion cards. Most things switched to being configured with software/BIOS when the industry moved to PCI bus.