Round Robin Advantage Vs Disadvantage

Duration: 9 min

This video lesson is available to enrolled students.

Return to /learn/LTI-MINDTREE-PREPARATION/operating-system/cpu-scheduling/round-robin-scheduling/asset-round-robin-advantage-vs-disadvantage after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. English Comprehension/Verbal Ability: Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Vocabulary, Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Subject Verb Agreement (Verb Noun Agreement), Tenses, Verb, Articles, Preposition, Conjunction, Pronoun, Noun, Adjectives, Adverb, Modals, Cloze Test (Cloze Passage), Active Passive Voice (Voice), Direct and Indirect Speech, Sentence Construction
  2. Logical Ability: Coding Decoding, Directions (Direction Test), Analogy, Inequality, Data Sufficiency, Series (Number and Letter Series) (Numerical Relations and Reasoning), Syllogisms, Seating Arrangements, Puzzle Solving (Puzzles), Blood Relations, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Ranking, Order and Sequence, Logical Sequence Of Words, Data Arrangement, Venn Diagram, Calendar, Clock
  3. Quantitative Ability: Logarithm, Permutation and Combination, Probability, Profit and Loss, Speed Time and Distance, Mixture and Alligation, Partnership, Simple Interest and Compound Interest, Percentage, Ratio and Proportion (Ratios), Average, Time and Work, Pipe and Cistern, Number System, Divisibility Rules, HCF LCM, Algebra, Powers and Exponents (Surds and Indices), Mensuration and Geometry, Age Problems, Data Interpretation, Sequence and Series (Series)
  4. Basic Analytical Ability: Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Cubes & Dices, Selection Decision Table (Decision Making)
  5. Computer Programming: Pseudo Codes, Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Java, Python for Placements by Yash Sir
  6. DBMS (Computer Science): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Transaction Management, Concurrency Control, Database Security & Authorization
  7. SQL (Computer Science): SQL
  8. OS (Computer Science): Introduction to OS, Process Management, CPU Scheduling, Deadlock, Process Synchronization, Threads & Process Creation, Memory Management, Virtual Memory, File Management
  9. Computer Networks (Computer Science): Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security
  10. Data Structures (Computer Science): Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  11. OOPs (Computer Science): Object Oriented Programming (OOPS)
  12. Software Engineering (Computer Science): Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  13. SVAR Conversational - Spoken English: Communication Assessment
  14. HR Interview: MR & HR Interview Preparation
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a comprehensive lecture on the Round Robin (RR) CPU scheduling algorithm. The instructor begins by explaining the core principles of RR, including the concept of a time quantum (q) and how it ensures fairness by giving each of the n processes in the ready queue a turn to execute for at most q time units. A key point is that the maximum waiting time for a process before its next quantum is (n-1)q. The lecture then transitions to the impact of the time quantum's size, explaining that a very large quantum makes RR behave like First-Come, First-Served (FCFS), while a very small quantum creates the illusion of multiple processors, a concept known as processor sharing. The video concludes with a detailed analysis of RR's advantages and disadvantages. Advantages include excellent average response time, making it ideal for time-sharing and interactive systems, and its nature as a preemptive SJF implementation. Disadvantages include the potential for longer processes to starve and the fact that performance is highly sensitive to the time quantum's value, as it affects both average response time and CPU utilization. A table of process metrics is used to illustrate the calculation of completion time, turn around time, and waiting time.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a slide defining the Round Robin (RR) scheduling algorithm. The instructor explains that if there are n processes in the ready queue and the time quantum is q, each process gets 1/n of the CPU time in chunks of at most q time units. He emphasizes that each process must wait no longer than (n-1)q time units for its next quantum. To illustrate this, he draws a timeline on the whiteboard, labeling processes P1, P2, and P3, and shows how they would be scheduled in a round-robin fashion, with each getting a slice of time q. He also writes the formula for the maximum waiting time as (n-1)q.

  2. 2:00 – 5:00 02:00-05:00

    The instructor discusses the effect of the time quantum's size. He states that if the time quantum is extremely large, RR behaves like the FCFS policy. Conversely, if the time quantum is extremely small (e.g., 1 millisecond), the RR approach is called processor sharing, where it creates the illusion that each of the n processes has its own processor running at 1/n the speed of the real processor. He draws a diagram to show the transition from a large quantum (max) leading to FCFS to a small quantum (min) leading to processor sharing. He also mentions that the effect of context switching on performance must be considered.

  3. 5:00 – 8:37 05:00-08:37

    The video presents a slide on the advantages and disadvantages of RR. Advantages include performing best in terms of average response time, making it suitable for time-sharing, client-server, and interactive systems, and being a kind of SJF implementation. The instructor then moves to the disadvantages: longer processes may starve, and performance is heavily dependent on the time quantum. He explains that a very small quantum gives a good average response time but causes many context switches, while a very large quantum results in poor average response time but fewer context switches and better CPU utilization. The video concludes with a table showing process metrics (P0 to P5) and a Gantt chart, which the instructor uses to calculate completion time, turn around time (TAT = CT - AT), and waiting time (WT = TAT - BT).

The lecture systematically builds an understanding of the Round Robin scheduling algorithm. It starts with the fundamental definition and fairness guarantee, using a timeline diagram to visualize the process. It then explores the critical parameter of the time quantum, showing how its size dictates the algorithm's behavior, from FCFS to processor sharing. Finally, it provides a balanced view by outlining the key advantages, such as excellent response time for interactive systems, and the main disadvantages, including starvation and the trade-off between response time and CPU utilization. The use of a process table and Gantt chart provides a practical example of how to calculate key performance metrics, reinforcing the theoretical concepts.

Loading lesson…