Preemption

Inside operating systems: understanding processes and scheduling Operating systems manage a computer’s resources. They run many tasks at once by dividing CPU time. A key idea is the concept of a process, which is a program in action. The OS uses scheduling to decide which process runs next. What is a process? A process is a running instance of a program. It uses memory, can wait for input, and may run tasks in stages. Each process has states: new, ready, running, waiting, and terminated. The OS keeps a list called the ready queue for processes waiting to use the CPU. ...

Inside Operating Systems Concepts Scheduling and Security Every running program waits for CPU time. The part of the operating system that decides who gets the next slice is called the scheduler. It keeps the system responsive and fair, but it also affects security. If scheduling is predictable, attackers can time actions to extract data; if it is too chaotic, important tasks may miss deadlines. Clear rules help both performance and protection. ...

Operating System Schedulers: How the Kernel Manages Tasks Behind every program you run, the kernel juggles many tasks. The OS scheduler decides which task runs on the CPU and for how long. It must balance speed, fairness, and energy use, while staying responsive to user input. The scheduler moves tasks through ready, running, waiting, and completed states, keeping the system busy without wasting time. Most modern kernels use a short-term scheduler that runs many times per second. Long- and medium-term schedulers decide what jobs enter the pool of ready tasks and how many stay in memory. The short-term scheduler chooses the next task to run and may preempt the current one if a higher-priority task arrives. ...