Conclusion of External Fragmentation

Duration: 2 min

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Module outline

  1. HPSC Interview Preparation: Interview Preparation
  2. Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis, DSA using Python
  3. Data Structure & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Sorting Algorithms, Minimum Spanning Trees, Time Complexity Analysis, Graph Theory, Shortest Path Algos
  4. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security
  5. Computer System & Organisation: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer
  6. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, SQL, File Organization & Indexing, Transaction Management, Concurrency Control
  7. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling
  8. Digital Logic & Circuits: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  9. Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Pushdown Automata & CFG, Turing Machines, Moore & Mealy Machines
  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. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Data Warehousing & Mining
  12. Introduction to Emerging Trends: Emerging Tech Trends
  13. Digital Society & Cyber Law: Society, Law & Ethics
  14. HPSC PGT Previous Year Paper:
  15. HPSC Assistant Professor Previous Year Paper:
  16. Live Sessions: HPSC Live Sessions, EMRS TGT/PGT Live Class
  17. Full Mock Test:
  18. HPSC PGT - MOCK Test Series:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The lecture focuses on methods to resolve external fragmentation in operating systems. The instructor presents two primary solutions: swapping processes to perform compaction and utilizing non-contiguous allocation. The first method involves swapping processes in and out of main memory at fixed intervals to consolidate free memory space, a process known as compaction or defragmentation. However, the instructor notes this is costly in terms of time, especially when the system is running. The second solution proposed is non-contiguous allocation, where a process is divided into parts and allocated to different areas of memory, eliminating the need for contiguous blocks. The instructor uses a whiteboard diagram to illustrate how processes can be split and placed in various memory locations, effectively utilizing fragmented space.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces solutions to external fragmentation using a slide titled 'How can we solve external fragmentation?'. He discusses swapping processes to create empty memory parts, explicitly mentioning 'Compaction, defragmentation' on the slide. He highlights that this solution is 'very costly in respect to time'. He then transitions to the second solution, 'non-contiguous allocation', explaining that a process can be 'divided into parts and different parts can be allocated in different areas'. He begins drawing a diagram on the whiteboard to visualize memory allocation, drawing a rectangle to represent memory and smaller shapes to represent processes.

  2. 2:00 – 2:25 02:00-02:25

    The instructor continues his explanation of non-contiguous allocation while pointing to the diagram he drew on the whiteboard. He circles a specific section of the memory diagram to emphasize how a process can be split. He reinforces the concept that processes do not need to be in one contiguous block. He gestures towards the diagram, showing how different parts of a process can reside in different areas of memory. This visual aid supports his verbal explanation that non-contiguous allocation solves the fragmentation issue by allowing flexible placement of process parts.

The lecture effectively contrasts two approaches to managing external fragmentation. While compaction is a viable method, its high time cost makes it less ideal for running systems. Non-contiguous allocation emerges as a more efficient alternative, allowing processes to be fragmented and placed in available memory holes. The instructor's use of the whiteboard diagram clarifies the abstract concept of non-contiguous allocation, showing students how memory can be utilized more effectively without requiring large, contiguous blocks.

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