Process Lifecycle
Easy+12 XPWatch one process travel its whole life: New → Ready ⇄ Running → Terminated, with detours to Waiting.
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Press Run to begin.
A process doesn't just run from start to finish — on a busy computer it's constantly paused and resumed. Press Run and follow one process through its states as the OS shares the CPU.
▸Why doesn't a process just run straight through?
Because the CPU is shared. Many processes want it, so the OS lets each run for a little while, then pauses it and lets another go. Your process keeps bouncing between 'Ready' (waiting its turn) and 'Running' (its turn now).
▸What's the difference between Ready and Waiting?
Ready means 'I could run right now, I just need the CPU' — it's in line for its turn. Waiting means 'I can't run yet even if offered the CPU, because I need something first' (like a file loading). A waiting process must go back to Ready before it can run again.
▸Why can't a Waiting process jump straight back to Running?
Fairness. When the thing it needed arrives, it rejoins the Ready line and waits its turn like everyone else — otherwise it could cut ahead of processes that have been patiently ready the whole time.
▸Who decides when it moves from Ready to Running?
The scheduler — a part of the OS whose whole job is picking which Ready process runs next. That's the very next topic: CPU scheduling.