N Process Solution using Semaphore

Duration: 8 min

This video lesson is available to enrolled students.

Return to /learn/AMCAT-PREPARATION/operating-systems/process-synchronization/semaphores-ordering/asset-n-process-solution-using-semaphore after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. Quantitative Ability: Percentage, Profit and Loss, Ratio and Proportion (Ratios), Average, Time and Work, Speed Time and Distance, Simple Interest and Compound Interest, Age Problems, Number System, Divisibility Rules, HCF LCM, Algebra, Permutation and Combination, Probability, Data Interpretation, Logarithm, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Speed Mathematics and Basic Mathematics
  2. Logical Reasoning: Seating Arrangements, Puzzle Solving (Puzzles), Data Arrangement, Coding Decoding, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Data Sufficiency, Venn Diagram, Inequality, Series (Number and Letter Series) (Numerical Relations and Reasoning), Logical Sequence Of Words, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Analogy, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning)
  3. Verbal Ability: Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Subject Verb Agreement (Verb Noun Agreement), Tenses, Articles, Preposition, Conjunction, Modals, Active Passive Voice (Voice), Direct and Indirect Speech, Vocabulary, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Sentence Completion (Fill in the blanks), Sentence Correction (Error Correction), Cloze Test (Cloze Passage), Facts, Inference and Judgements
  4. Programming Fundamentals (Technical): C Fundamentals
  5. Data Structures (Technical): Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  6. Algorithms (Technical): Algorithm Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Time Complexity Analysis, Advanced Algorithms
  7. OOPs (Technical): Object Oriented Programming (OOPS)
  8. DBMS (Technical): 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
  9. SQL (Technical): SQL
  10. Operating Systems (Technical): 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
  11. Computer Networks (Technical): 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
  12. Software Engineering (Technical): Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  13. Coding/Automata Round: Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Java, Python for Placements by Yash Sir, Pseudo Codes
  14. Personality / Behavioral Assessment: Behavioral Assessment (Behavioral Competency Profiling) (Psychometric Test)
  15. Writing Assessment: English Writing Ability
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture explains how Semaphores solve the Critical Section Problem for n-processes, overcoming the limitations of Peterson's solution which was restricted to two processes. The instructor presents a generic process structure P_i() containing an initial section, a wait operation, a critical section, a signal operation, and a remainder section. He emphasizes that for mutual exclusion, the semaphore is initialized to 1. The lecture then defines semaphores as integer variables accessed only via atomic operations wait(S) and signal(S), historically known as P(S) and V(S). The implementation details of these operations are shown, where wait decrements the value and signal increments it, ensuring synchronization.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by stating that Peterson's solution is confined to just two processes, whereas general systems require an n-process solution provided by Semaphores. He displays a code block for a process P_i() structured with a While(T) loop. Inside the loop, he lists the Initial Section, wait(s), Critical Section, signal(s), and Remainder Section. He explicitly writes on the board that while solving the Critical Section Problem, the semaphore S is initialized to 1. He writes P_1, P_2, ..., P_n to represent the multiple processes involved.

  2. 2:00 – 5:00 02:00-05:00

    The lecturer details the specific roles of the synchronization primitives within the process code. He points to wait(s) and labels it as the Entry Section (ES), explaining that this is where the process attempts to enter the critical section. He then points to signal(s) and labels it as the Exit Section (ES), indicating where the process releases the resource. He reiterates the initialization S=1 on the board. He discusses how multiple processes P_1 through P_n will contend for the critical section, and the semaphore mechanism ensures that only one process can proceed at a time based on the value of S.

  3. 5:00 – 8:17 05:00-08:17

    The lecture transitions to a slide titled Operation System Solution to formally define Semaphores. The slide states that a semaphore S is a simple integer variable accessed only through two standard atomic operations: wait(S) and signal(S). The instructor notes that wait(S) was originally termed P(S) and signal(S) was V(S). He shows the code definition for wait(S) which includes a while(s<=0); loop followed by s--;, and signal(S) which simply performs s++;. He explains that these operations are atomic, meaning they cannot be interrupted, which is crucial for preventing race conditions in the synchronization logic.

The lesson progresses from identifying the limitations of previous solutions to introducing a robust mechanism for n-process synchronization. By defining the process structure and the atomic nature of semaphore operations, the instructor establishes the foundation for solving the critical section problem. The distinction between the logical structure of the process and the underlying atomic implementation of the semaphore operations is clearly drawn, highlighting how wait and signal manage access to shared resources.

Loading lesson…