Fundamentals of Scheduling in Operating System

Threads and scheduling are key components of an operating system that help improve system efficiency and performance. Through threads, multitasking and efficient use of resources can be achieved, while scheduling algorithms ensure that the CPU is used most effectively to reduce execution time.

Scheduling is the process in an operating system that decides which process or thread will use the CPU and when. Its main purpose is to increase system efficiency and properly control execution.

1. User-Level Scheduling: The user decides how CPU time will be used. This is particularly seen in multithreaded systems.

2. Kernel-Level Scheduling: The operating system kernel decides which process or thread gets the CPU and for how long.

1. First-Come, First-Served (FCFS): The process that arrives first gets the CPU first.

2. Shortest Job First (SJF): The process with the shortest execution time is executed first.

3. Round Robin: Each process gets a fixed amount of CPU time, called a time slice or time quantum.

4. Priority Scheduling: Each process is assigned a priority, and the process with the higher priority is executed first.

5. Multi-Level Queue Scheduling: Processes are divided into different priority queues, and each queue has its own scheduling algorithm.

6. Multi-Level Feedback Queue: Processes can be moved between different queues based on their execution time and behavior.