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.