IRQ15

IRQ15 is an interrupt request line on the ISA bus architecture, commonly found in older IBM PC compatible computers. Interrupts are signals that a hardware device sends to the processor to indicate that it needs attention. IRQ lines provide a way for multiple devices to share this interrupt mechanism. IRQ15 is typically assigned to the second enhanced floppy disk controller, if present. In systems where this controller is not used or is absent, IRQ15 may be available for other devices. However, due to its association with the floppy drive, it is less commonly used for other peripherals compared to some other IRQ lines. Conflict can arise if multiple devices attempt to use IRQ15 simultaneously, leading to system instability or malfunction. Modern computer systems, which predominantly use PCI or PCIe buses, have a different interrupt handling mechanism and do not directly use the ISA IRQ lines. Therefore, IRQ15 is largely a legacy component relevant to older hardware configurations.