Interrupt Service Routine (ISR)

[shrink_tubing]

Hi there!

Nice to be on here again Stuck doing my uni stuff at the moment and it's boring to be honest. Can't wait to get back to C++ stuff.

Interesting here and there though I guess. Anyways.. I came across this. Now the course describes an ISR as occurring whenever there is for example some Input/Output stuff going on. Rather than sit there and wait for a device to finish giving input, or finish receiving output, the processor will do a context switch and run another process.

Ok.. but that means surely for a one core system that the processor is not involved in dealing with the ISR. But something's certainly active and handling data, but not the processor.

So what is that thing? It must be some sort of hardware on the motherboard dealing with it, but I don't know what it is?

Hope that makes sense.

Thanks

[john.c]

An ISR is a running program (hence "routine"). So a core (perhaps the only core) will be running it.
Interrupt handler - Wikipedia

There is something called DMA where a subsystem of the computer other than the CPU can move data in or out of memory so that the CPU doesn't need to wait (unless it is waiting on that data).
Direct memory access - Wikipedia

[shrink_tubing]

I'll check out those links John thanks very much