Reader Writer Problem

Duration: 6 min

This video lesson is available to enrolled students.

Return to /learn/SSC-JE-IMD-SCIENTIFIC-ASSISTANT-COMPUTER-SCIENCE/operating-system/process-synchronization/classical-problems/asset-reader-writer-problem after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. General Intelligence & Reasoning: Analogy, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Logical Sequence Of Words, Syllogisms, Venn Diagram, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Data Sufficiency, Puzzle Solving (Puzzles), Data Arrangement, Cubes & Dices, Calendar, Clock, Arithmetic, Number System, HCF LCM, Verbal Analogy (Word Based Analogy), Visual Recognition and Figure Completion, Paper Folding and Cutting, Transformation of Shapes, Clocks and Calendars, Direction Sense, Cubes and Dice, Patterns in Two-Dimensional Figures, Seating Arrangements, Analogy and Classification, Logical Deduction and Induction, Alphabet and Word Tests, Mathematical Operations, Series Completion, Simplification and Approximation, Coding and Decoding, Numerical Reasoning, Assembling and Grouping of Shapes, Three-Dimensional Patterns and Visualization, Vocabulary, Number System, Averages, Mixtures and Alligation, Simple and Compound Interest, Percentages, Algebra, Speed, Time and Distance, Seating and Arrangement Puzzles, Traverse Surveying, Order, Ranking and Sequence, Constraint Puzzles, Syllogisms and Venn Diagrams, Reading Comprehension, Critical Reasoning, Permutations and Combinations, Narrative Sequencing, Project Monitoring, Resources and Safety, Profit, Loss and Discount, Ratio and Proportion, Time and Work, Mensuration, Data Interpretation, Powers, Surds and Logarithms, Sequences and Series, Articles and Determiners, Sentence Completion, Data Sufficiency, Blood Relations, Simple Interest and Compound Interest, Mixture and Alligation, Sequence and Series (Series), Speed Time and Distance, Algebra, Profit and Loss, Powers and Exponents (Surds and Indices), Permutation and Combination
  2. General Awareness: Physics, Chemistry, Biology, History, Geography, Polity, Indian Economy, Environment, Static General Knowledge, GK- Current Affairs, Artificial Intelligence, MS Office Applications, Terms & Abbreviations, Keyboard Shortcuts, Evolution of Indian Banking (Banking & Financial Awareness), Emerging Tech Trends
  3. Engineering Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Linear Algebra, Calculus, Probability, Statistics, Signal Space and Optimum Detection, Probability, Statistics
  4. Digital Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep, Number Systems and Codes, Registers and Counters, Boolean Algebra and Logic Gates, Microprocessors and Microcontrollers, Logic Families and CMOS Logic, Microprocessors, Logic Gates and Boolean Algebra, Minimization of Boolean Functions, Timing, Hazards and Testing, Logic Families, Combinational Logic Design, Arithmetic Circuits, Waveform Generators and Timer Circuits, Semiconductor Memories and Programmable Logic Devices, Combinational Logic Circuits, Latches and Flip-Flops, Finite State Machines, Sequential Circuits and State Machines, Minimization of Boolean Functions, Arithmetic Circuits, Latches and Flip-Flops, Number Systems and Codes, Registers and Counters
  5. Computer Organisation & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer, Register Transfer and Microoperations, Semiconductor Memories and Programmable Logic, Processor Organization and Instructions, Memory Hierarchy and Input/Output, Registers and Counters
  6. Programming & Data Structures: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, HTML Basics, OOPS with C++, Java, Object Oriented Technology
  7. Databases: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Database Security & Authorization
  8. Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos
  9. Theory of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory
  10. Compiler Design: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  11. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Security, Windows OS, Distributed Systems, Unix OS, Linux OS
  12. Computer Networks: Introduction to CN, 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, Data Communication, Website, Browser & Services, Web Design & Development, Network Security, Cyber Threats and Malware Attacks, Cyber Safety and Security
  13. Full Length Mock Tests:
  14. Sectional Tests:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture introduces the classic Reader-Writer problem in the context of operating systems and concurrent processes. The instructor sets up a scenario where a database is shared among several processes. He distinguishes between 'readers,' which only read data, and 'writers,' which perform both read and write operations. The central challenge is managing concurrent access to prevent data inconsistency. The instructor explains that while multiple readers can access the shared data simultaneously without adverse effects, any interaction involving a writer (Reader-Writer, Writer-Reader, or Writer-Writer) can lead to 'chaos' or data corruption. Consequently, the lecture outlines the fundamental constraints required to generate a valid solution for this synchronization problem. The instructor uses a database table example to visualize the data being shared.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by defining the problem using a visual example of a database table containing movie titles and release years. He explains that some processes are readers (read-only) and others are writers (read/write). He states that if two readers access the shared data simultaneously, no adverse effects result. However, if a writer and another process access the database simultaneously, chaos may ensue. To illustrate permissible concurrency, he writes 'RR' on the whiteboard, indicating that Reader-Reader access is allowed. The visible database shows columns like 'title', 'release_year', 'length', and 'replacement_cost'. The slide text reads 'Suppose that a database is to be shared among several concurrent processes.' He gestures with his hands to emphasize the concept of sharing.

  2. 2:00 – 5:00 02:00-05:00

    The instructor continues by illustrating the problematic concurrency scenarios. He writes 'RW', 'WR', and 'WW' on the board, circling them to show that any combination involving a writer causes issues. He then transitions to a slide titled 'Points that needs to be taken care for generating a Solutions'. He reads and explains the first point: the solution may allow more than one reader at a time, but should not allow any writer. He underlines this text to emphasize the priority of allowing concurrent readers. The slide also states, 'To ensure that these difficulties do not arise, we require that the writers have exclusive access to the shared database while writing to the database.' He points to the text to guide the viewer's attention.

  3. 5:00 – 5:39 05:00-05:39

    The instructor focuses on the second constraint listed on the slide. He explains that the solution must strictly not allow any reader or writer while a writer is performing a write operation. He underlines 'write operation' and 'exclusive access' to highlight the critical nature of writer exclusivity. The slide text is clearly visible, providing the formal requirements for the synchronization algorithm that will likely be discussed next. He gestures towards the text to reinforce the point. The text 'The solution should strictly not allow any reader or writer, while a writer is performing a write operation' is highlighted.

The lecture progresses from defining the Reader-Writer problem and its constraints to outlining the specific requirements for a solution. It establishes that while readers can share data, writers require exclusive access to prevent data corruption. The instructor uses visual aids like a database table and whiteboard annotations to clarify the concepts of concurrent access and the resulting conflicts.

Loading lesson…