What is usually the critical performance requirement in an interactive operating system? What is the difference between preemptive and non-preemptive scheduling?

First question: Response time.

Explanation:

When we're talking about the interactive operating system, the most important thing is the response time, because the user makes an action and the system must response as soon as possible.

For example:

A video game user pushes a button, in this case, the user's character must do an action like jump or run, this response is so fast.

Difference between preemptive and non-preemptive scheduling

- Preemptive scheduling: assign process for a limit time.

- Non-Preemptive scheduling: assign process until changing the waiting state.

- Preemptive scheduling: Processes are interrupted in the middle of execution.

- Non-Preemptive scheduling: Processes are not interrupted in the middle of execution.