Full marks6/6
The OS uses multitasking to share the CPU. It gives each process, such as the music player and the video editor, a small time slice so they appear to run at the same time. It decides which ready process is next and how long it runs. When the video editor is opened, the OS creates a process and moves its instructions into RAM so it is ready; when the CPU is free it moves it to running. If the download is waiting for data, the OS marks it blocked so the CPU is not wasted. If the printer runs out of paper, a hardware interrupt tells the CPU to stop and run the interrupt handler; afterwards the OS returns to the process.
Why: Covers scheduling with time slices, process states (ready, running, blocked) and interrupts, with sustained application to the music, video editor and download. Level 3.
Some marks4/6
The operating system uses multitasking so the music and video editor can run at the same time. It gives each program a small amount of time on the CPU. When a program is opened it creates a process and puts it in RAM. If a process is waiting for input it is blocked.
Why: Covers CPU sharing and process states, with some application, but says nothing about interrupts. Level 2.
Some marks1/6
The operating system manages processes by giving each program a turn on the CPU. This stops the computer crashing when too many programs are open.
Why: Gives only a basic, undeveloped point about giving each program a turn, with no linkage or application. Level 1.