Summary of L-2.1: Process Scheduling Algorithms (Preemption Vs Non-Preemption) | CPU Scheduling in OS

Summary of Video: L-2.1: Process Scheduling Algorithms (Preemption Vs Non-Preemption) | CPU Scheduling in OS

The video discusses the concept of Scheduling Algorithms in operating systems, focusing on how processes are selected from a ready queue to be executed by the CPU. It introduces two main types of scheduling: preemptive and non-Preemptive Scheduling.

Main Ideas and Concepts:

• Scheduling Algorithms Overview:
  • Scheduling Algorithms determine which process in the ready queue is executed by the CPU.
  • The ready queue is located in RAM and can contain multiple processes.
• Uni-Processor System:
  • In a uni-processor system, only one process can be executed at a time.
• Types of Scheduling:
  • Preemptive Scheduling:
    • A currently running process can be interrupted and moved back to the ready queue.
    • The CPU can switch to another process before the current process completes its execution.
    • Reasons for preemption:
      • Time Quantum: The CPU allocates a fixed time for each process (e.g., 2 seconds).
      • Responsiveness: Allows all processes to receive attention more quickly.
      • Priority: Higher priority processes can interrupt lower priority ones.
      • Shortest Job First: Shorter processes may be executed first to improve efficiency.
  • Non-Preemptive Scheduling:
    • Once a process is allocated to the CPU, it runs to completion before any other process is executed.
    • The process will not return to the ready queue until it finishes execution.
• Examples and Analogies:
  • The speaker uses a classroom analogy where students (processes) ask questions (tasks) to illustrate preemptive and non-Preemptive Scheduling.
• Key Scheduling Algorithms:
  • Preemptive Algorithms:
    • Shortest Remaining Time First (SRTF)
    • Longest Remaining Time First (LRTF)
    • Round Robin
    • Priority (can be both preemptive and non-preemptive)
  • Non-Preemptive Algorithms:
    • First Come First Serve (FCFS)
    • Shortest Job First (SJF)
    • Longest Job First (LJF)
    • Highest Response Ratio Next (HRRN)
    • Multi-level Queue
    • Multi-level Feedback Queue

Methodology/Instructions:

• Understand the difference between preemptive and non-Preemptive Scheduling.
• Familiarize yourself with the various Scheduling Algorithms and their applications.
• Practice numerical problems related to Scheduling Algorithms for better comprehension.

Speakers/Sources Featured:

• The speaker from Gate Smashers (specific name not provided in the subtitles).

Notable Quotes

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Category

Educational

Video