Working Set Strategy

Duration: 6 min

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Module outline

  1. About Course: About the Course
  2. Paper 1 | General Studies: State Wise GK
  3. Paper 1 | Information and Communication Technology: Role of Internet and Web Services, Security in Mobile and Wireless Computing
  4. Paper 1 | Current Affairs: GK- Current Affairs
  5. Paper 2 | Discrete Mathematical Structure: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Probability
  6. Paper 2 | Digital Computer Organization And Architecture: Number System, Number Representation, Sequential Circuits, Combinational Circuit, Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer
  7. Paper 2 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  8. Paper 2 | Programming Languages & Object-Oriented Programming Concepts: Java, OOPS with C++, Java Fundamentals, Array, String, IO & References
  9. Paper 2 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  10. Paper 2 | Data Structure And Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Minimum Spanning Trees, Advanced Algorithms
  11. Paper 2 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS
  12. Paper 2 | 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
  13. Paper 2 | 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
  14. Paper 2 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Transaction Management, Concurrency Control, Database Recovery, Database Security & Authorization, Enhanced Data Models
  15. Paper 2 | Computer Network And Information Security: Introduction to CN, Data Communication, Application Layer, Hardware basics, Cyber Threats and Malware Attacks, Network Security, 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
  16. Paper 2 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  17. Paper 2 | Current Trends & Technologies: Emerging Tech Trends, Approaches to AI, Search Algorithms, Game Playing, Knowledge Representation, Planning, Multi Agent Systems, Fuzzy Sets, Natural Language Processing, Artificial Neural Networks, Genetic Algorithms, Artificial Intelligence, Data Warehousing & Mining, Electronic Data Interchange and E-Commerce, Terms & Abbreviations
  18. Paper 2 | Full Length Mock Tests:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture introduces the Working Set Strategy in operating systems, focusing on the locality model of process execution. The instructor explains that a program moves through different localities, where a locality is defined as a set of pages actively used together. Using a page reference table, he demonstrates how to calculate the working set at specific time points ($t_1$ and $t_2$) by analyzing the pages referenced within a fixed window size ($\Delta$). The lesson highlights the dynamic nature of memory requirements as a process transitions between different localities.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video begins with a slide titled 'The Working Set Strategy'. The instructor reads the first bullet point: 'This approach defines the locality model of process execution.' He then explains the second point, stating that as a process executes, it moves from locality to locality. He defines a locality as 'a set of pages that are actively used together.' He points to the third bullet point, noting that a program is generally composed of several different localities which may overlap. He gestures towards the 'page reference table' at the bottom of the slide, which lists a sequence of numbers like 2, 6, 1, 5, 7, 7, 7, 7, 5, 1, 6, 2, 3, 4, 1, 2, 3, 4, 4, 4, 3, 4, 3, 4, 4, 4, 1, 3, 2, 3, 4, 4, 4, 3, 4, 4, 4.

  2. 2:00 – 5:00 02:00-05:00

    The instructor focuses on the diagram below the table, which shows time points $t_1$ and $t_2$ with a window size $\Delta$. He explains that the working set at time $t$, denoted as $WS(t)$, consists of the pages referenced in the interval $[t - \Delta, t]$. He draws a box around the sequence ending at $t_1$, which includes the numbers 2, 6, 1, 5, 7, 7, 7, 7, 5, 1. He identifies the unique pages in this window as {1, 2, 5, 6, 7}. He writes $WS(t_1) = \{1, 2, 5, 6, 7\}$ and counts the number of unique pages, writing a '5' below it to represent the working set size. He then moves to $t_2$, drawing a box around the sequence ending there, which includes 3, 4, 4, 4, 3, 4, 3, 4, 4, 4, 1. He identifies the unique pages as {3, 4}. He writes $WS(t_2) = \{3, 4\}$ and counts the unique pages, writing a '2' below it.

  3. 5:00 – 5:40 05:00-05:40

    The instructor concludes the example by comparing the two working sets. He points to the numbers 3 and 4 in the reference table, emphasizing that these are the pages currently being used at time $t_2$. He explains that the working set size has decreased from 5 to 2, indicating a shift in the process's locality. He reiterates that the working set strategy helps in determining the number of frames a process needs in memory to avoid thrashing. He gestures back and forth between the two time points to show the transition from one locality to another.

The lesson progresses from theoretical definition to practical application. It starts with the definition of locality and the working set strategy, then moves to a concrete example using a page reference string. The instructor demonstrates how to calculate the working set size at different time points by analyzing the recent history of page accesses within a fixed window $\Delta$. This illustrates the dynamic nature of memory requirements for a process.

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