Conclusion of External Fragmentation

Duration: 2 min

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Module outline

  1. Discrete Mathematics: Permutation, Combination and Probability / क्रमचय, संचय एवं प्रायिकता, Set Theory, Relations, Functions, Propositional and Predicate Logic, Graph Theory, Group Theory
  2. Digital Logic: Digital Systems & Boolean Basics, Boolean Expression, Boolean Minimization, Logic Gates & Hardware, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep
  3. Computer Organization and Architecture: Basics of COA, Programming the Basic Computer, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Pipelining, Multiprocessors
  4. Programming: Language Design, C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++
  5. Data Structures: Introduction to DS, Array, Linked List, Stack, Queue, Tree, Graphs, Hashing
  6. Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  7. Theory of Computation: Grammar, Regular Language Properties, Moore & Mealy Machines, Turing Machines
  8. 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, Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Pushdown Automata & CFG, Complexity Theory
  9. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Security
  10. Database Management Systems: 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, ORDBMS, NoSQL
  11. Computer Networks: 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
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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