Understanding Page Fault and Page Fault Service

Duration: 7 min

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Module outline

  1. Numerical Ability & Problem Solving: Speed Mathematics and Basic Mathematics, Arithmetic, Number System, HCF LCM, Divisibility Rules, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Mixture and Alligation, Time and Work, Pipe and Cistern, Speed Time and Distance, Age Problems, Partnership, Data Interpretation, Mental Ability, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Algebra, Statistics, Logarithm, Mensuration and Geometry, Permutation and Combination, Probability, Sequences and Series, Powers, Surds and Logarithms, Subject-Verb Agreement, Sentence Completion, Geometry, Sentence Structure and Correction, Data Sufficiency, Trigonometry, Measurement and Quantity Take-Off, Signal Space and Optimum Detection, Probability, Statistics, Algebra, Time and Work, Speed, Time and Distance, Data Interpretation, Combinatorics
  2. Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Blood Relations, Directions (Direction Test), Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Logical Sequence Of Words, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence, Selection Decision Table (Decision Making), Alphabet and Word Tests, Numerical Reasoning, Number System, Averages, Mixtures and Alligation, Percentages, Series Completion, Analogy and Classification, Patterns in Two-Dimensional Figures, Coding and Decoding, Mathematical Operations, Direction Sense, Logical Deduction and Induction, Syllogisms and Venn Diagrams, Critical Reasoning, Order, Ranking and Sequence, Reading Comprehension, Profit, Loss and Discount, Constraint Puzzles, Traverse Surveying, Ratio and Proportion, Mensuration, Permutations and Combinations, Clocks and Calendars, Assembling and Grouping of Shapes, Transformation of Shapes, Three-Dimensional Patterns and Visualization, Cubes and Dice, Vocabulary, Blood Relations
  3. General Knowledge & Current Affairs (India + Rajasthan): History, Geography, Polity, Indian Economy, Static General Knowledge, State Wise GK, GK- Current Affairs, Environment, Physics
  4. Computer Fundamentals & Operating Systems: Basics of COA, Floating Point Rep, Digital Systems & Boolean Basics, Number Representation, Number System, Introduction to OS, File Management, Windows OS, Unix OS, Linux OS, Register Transfer and Microoperations, Virtual Memory
  5. Computer Networks: Introduction to CN, Data Communication, DLL: Error Control, DLL: Access Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Application Layer, Hardware Basics, Network Security
  6. Cyber Security: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security, Ethical Hacking
  7. Programming (C & OOP): C Fundamentals, Control Flow, Arrays & Pointers, Functions, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Operators & Expressions, Sorting Algorithms, Java Fundamentals, Java
  8. MS Office & Data Processing: MS Office Applications, Basics of DBMS
  9. Internet & Web Technology: Society, Law & Ethics, Terms & Abbreviations, Keyboard Shortcuts, Emerging Tech Trends, Artificial Intelligence, Emerging Technologies, Internet Fundamentals, Website, Browser & Services, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The lecture covers fundamental concepts of virtual memory management, specifically focusing on demand paging and page fault handling. The instructor begins by explaining that pages are loaded into main memory only when needed, which optimizes memory usage and reduces swap time. He introduces the valid-invalid bit scheme used by hardware to distinguish between pages currently in memory and those on disk. The session transitions to page faults, defining them as occurrences when a process accesses a page not in main memory. The instructor details the steps to handle these faults, including checking reference validity, finding free frames, and scheduling disk reads, supported by a flowchart diagram.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a slide titled 'Basic Concepts' and the 'KG' logo. The on-screen text explains that when a process starts, no page is loaded into main memory before demand, avoiding unnecessary reads and decreasing swap time. The instructor points to a diagram showing 'logical memory' with pages 0-7 labeled A-H. Next to it is a 'page table' with columns for 'frame' and 'valid-invalid bit'. He explains that hardware is needed to distinguish pages in memory from those not in memory, introducing the valid-invalid bit scheme. He points to the 'physical memory' column on the right, showing frames 0-15, and a cylinder representing secondary storage containing pages A-H. He writes 'SM' (Secondary Memory) next to the cylinder.

  2. 2:00 – 5:00 02:00-05:00

    The instructor continues analyzing the page table. He points to row 0, showing Page A maps to Frame 4 with a valid bit 'v'. He moves to row 3, showing Page D maps to Frame 3 with an invalid bit 'i', indicating Page D is not in physical memory. He highlights row 5, where Page F maps to Frame 9 with a valid bit 'v', and points to Frame 9 in the physical memory list which contains 'F'. He contrasts this with the disk, where 'F' is also stored. He emphasizes that the valid bit tells the system if a page is resident in RAM. If the bit is 'i', the page is on disk. He circles the 'F' in the page table and points to the corresponding frame in physical memory to reinforce the mapping. He also points to the empty frames in physical memory (e.g., frame 0, 1, 2, 5, 6, 7, 8, 10-15) to show available space.

  3. 5:00 – 7:16 05:00-07:16

    The slide changes to 'Page Fault'. The text defines a page fault as occurring when a process tries to access a page not in main memory. The instructor lists steps to handle this: if the reference is invalid, terminate the process; if valid but not in memory, page it in. He points to the text 'We find a free frame' and 'We schedule a disk operation'. A flowchart diagram illustrates the process: (1) Reference, (2) Trap, (3) Page on backing store, (4) Bring in missing page, (5) Free frame, (6) Restart instruction. He points to each numbered step in the diagram, explaining the flow from the initial memory reference to the trap handler, finding a free frame, reading the page from disk, and restarting the instruction. He gestures with his hands to emphasize the steps.

The lesson progresses from the basic mechanism of demand paging using valid-invalid bits to the specific handling of page faults. It establishes that pages are loaded on demand to save memory, managed via a page table. When a page is accessed but not in memory (indicated by an invalid bit), a page fault occurs. The system then handles this by checking validity, finding a free frame, reading the page from disk, and restarting the instruction, ensuring efficient memory management.

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