hi.could you explain to me how the IRQ system works and why it is necessary ? use the mouse as an example of a device that use this system and explain to me the process of moving the mouse and how the IRQ system will get the information to the cpu.also explain to me what it mean s that IRQ2 cascade IRQ9 and IRQ9 IRQ2 to IRQ2. please illustrate the explanation with a simple drawing showing me the two interrupt controller chips,the expansion bus and cpu. Many thanks!
