Linux on Amiga: Executive turns Amiga Exec Kernel into Linux -  

With regard to interrupts this will depend on the CPU but the operating system will register interrupt service routine addresses for code that will deal with a given interupt. When the interrupt occurs the CPU will deal with it immediately (again the precise details are cpu specific) and run that ISR code. The ISR code will have to deail with the nature of the interrupt and might deal with it then and there or (in the case with windows) they get queued up and dealt with at a different level of the OS through the driver code). This approach allows for drivers to be written to run in user mode rather than kernel mode - user mode drivers don't have access to memory directly and have a virtual address space which makes for a more robust operating system as a user mode driver can't crash the system (in theory).

I remember having my imagine 3d locking my A1200, but there was a program rhat allow to lower its priority, after setting its priority lower it was like it wasn't even running (it rendered with only a few seconds more but the rest of the computer worked as if ot wasn't running)

Great👍

With Windows the priorities are only used when there is competition for CPU resource - most of the processes on a Windows machine are background processes that only do stuff when responding to an other event (e.g. a timer or when triggered through the actions of another process (like a virus checker). Processes that are active - e.g. your browser still have downtime whilst they are waiting for other stuff to happen - e.g. responses to network requests or perhaps writing to disk etc. The scheduler takes into account whether a process needs to be executed at a specific point in time - the kernel will wake a process back up when a call to the kernel is completed and the process (well thread) can continue. Where you have a thread that is actively doing something where it will keep consuming cpu cycles without creating gaps (perhaps a complex calculation) then this is where priorities come in - theads with higher priorities will be allocated a greater amount of run time compared to processes with lower priority. Realtime is a special priority which was for real time code which is sensitive to timing - an attempt by microsoft to try to lure realtime system designers to use windows rather than dedicated hardware. Setting the wrong type of process to realtime can hang the system as the operating system doesn't get to run it's processes until the realtime process completes.

I have trust issues with you 😂