Methods of Recovery

Duration: 4 min

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Inside: a video lesson and guided study material.

Module outline

  1. Communication Round: Vocabulary, Subject Verb Agreement (Verb Noun Agreement), Tenses, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Direct and Indirect Speech, Active Passive Voice (Voice), Verbal Analogy (Word Based Analogy), Articles, Preposition, Conjunction, Sentence Construction, English Writing Ability, Communication Assessment
  2. Quantitative Aptitude: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Speed Time and Distance, Percentage, Average, Powers and Exponents (Surds and Indices), Time and Work, Mensuration and Geometry, Age Problems, Pipe and Cistern, Probability, Profit and Loss, Simple Interest and Compound Interest, Algebra
  3. Analytical and Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Directions (Direction Test), Ranking, Order and Sequence, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Logical Sequence Of Words, Puzzle Solving (Puzzles), Syllogisms, Seating Arrangements, Calendar, Clock, Blood Relations, Cubes & Dices, Venn Diagram, Analytical Reasoning (Counting Figures Reasoning)
  4. Cognizant Gaming Aptitude: Gamified / Game Based Aptitude
  5. Java (Cluster 1): Java
  6. ANSI SQL MySQL (Cluster 1,2,3): SQL
  7. HTML, CSS, JavaScript (Cluster 1,3): HTML, CSS, JavaScript
  8. Python (Cluster 2): Python for Placements by Yash Sir
  9. Cloud Fundamentals (Cluster 2): Emerging Tech Trends
  10. C# (Cluster 3): C#
  11. OOPs: Object Oriented Programming (OOPS)
  12. Technical Assessment (Coding): Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Pseudo Codes
  13. Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  14. DBMS: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, ORDBMS, Database Security & Authorization, Query Processing & Optimization, Enhanced Data Models, Data Warehousing & Mining, Big Data Systems, NoSQL
  15. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Linux OS, Security, Distributed Systems, Virtual Machines
  16. Computer Networks: 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, Mobile Technology, Cloud Computing and IoT, Cyber and Info Security
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational segment focuses on deadlock recovery mechanisms within operating systems. The instructor explains two primary methods for breaking a deadlock: process termination and resource preemption. He illustrates these concepts using a whiteboard diagram involving three processes (P1, P2, P3) to demonstrate how aborting a single process might not fully resolve the circular wait if other processes remain locked. The lecture then transitions into the policy decisions required for victim selection, discussing cost factors, rollback strategies, and the risk of starvation.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by defining 'Process Termination' and 'Pre-empt Resource' as strategies to break circular waits. On the slide, the text reads: 'Process Termination: One is simply to abort one or more processes to break the circular wait.' He then draws a diagram with an oval containing 'P1 P2 P3'. To illustrate termination, he crosses out 'P1' with a large 'X'. He explains that while P1 is aborted, P2 and P3 might still be in a deadlock state, indicated by the circular arrows he draws between them. This visual demonstration highlights that simply terminating one process does not guarantee the resolution of the entire deadlock situation if the remaining processes are still waiting on each other. He emphasizes that breaking the cycle is the primary goal. The instructor also mentions that pre-empting resources is another way, but it requires rolling back the process.

  2. 2:00 – 4:21 02:00-04:21

    The discussion shifts to 'How to choose a victim' when partial termination is used. The slide text states: 'This determination is a policy decision, similar to CPU-scheduling decisions.' The instructor explains that the goal is to abort processes with the minimum cost. He introduces the concept of 'Rollback,' noting that if a resource is preempted, the process must be rolled back to a safe state. The slide text mentions: 'Since, in general, it is difficult to determine what a safe state is, the simplest solution is a total rollback: abort the process and then restart it.' Finally, he addresses 'Starvation,' warning that the same process might always be picked as a victim, preventing it from completing its execution. He suggests including the number of rolls in the cost factor to mitigate this.

The lecture effectively bridges theoretical deadlock recovery methods with practical implementation challenges. By moving from the basic act of termination to the nuanced selection of victims and the management of rollback states, the instructor provides a comprehensive view of how operating systems handle resource contention. The visual aids, particularly the crossing out of processes and the slide text regarding cost and starvation, reinforce the economic and policy-based nature of these system decisions. The transition from simple termination to complex victim selection strategies underscores the importance of system stability and fairness in resource allocation. This holistic approach ensures that recovery mechanisms are both effective and equitable.

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