Basics of Space Allocation in Contiguous Allocation

Duration: 11 min

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  1. About Course: About the Course
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  3. Computer Networks & Cybersecurity: 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
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  6. Digital Logic & Computer Organization: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, 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. TOC & Compiler: 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, 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
  8. Discrete Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic
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  12. Other Recurring CS Topics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, Multimedia
  13. Live Classes: ISRO Live classes
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AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video lecture provides a detailed explanation of memory allocation strategies in operating systems, specifically focusing on contiguous allocation methods. The session begins by defining the 'First fit policy,' outlining its mechanism of searching memory from the base to allocate the first capable partition, and listing its pros and cons. The lecture then transitions to 'Variable size partitioning,' where the instructor uses hand-drawn diagrams to illustrate how memory is treated as a single chunk and dynamically divided based on process requests, ensuring remaining space is reused. Finally, the concept of 'Fixed size partitioning' is introduced, highlighting the issue of internal fragmentation when a process is smaller than its allocated partition. Visual analogies involving tables of different shapes and sizes are used to clarify these abstract concepts.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a slide titled 'First fit policy'. The text defines the policy as searching memory from the base to allocate the first partition capable enough. Bullet points list advantages such as being 'simple, easy to use, easy to understand' and disadvantages like 'poor performance, both in terms of time and space'. The instructor stands to the side, gesturing towards the text to emphasize these points.

  2. 2:00 – 5:00 02:00-05:00

    The slide changes to 'Space Allocation Method in Contiguous Allocation' focusing on 'Variable size partitioning'. The text explains that memory is treated as a whole chunk initially. The instructor draws a long horizontal rectangle representing memory, labeling it '100'. He draws vertical lines to partition it into segments and writes numbers below: '15', '40', '25', '20', '20'. He explains that exactly the requested space is allocated if possible, and the remaining space is reused.

  3. 5:00 – 10:00 05:00-10:00

    The instructor uses a visual analogy with tables to explain sizing. A slide shows 'Circle' tables with capacities 2, 4, 8, 10 and 'Rectangle' and 'Square' tables with capacities 6, 2, 4. The slide then switches to 'Fixed size partitioning'. The text states memory is divided into fixed size partitions, and remaining space is wasted internally. The instructor draws a row of fixed rectangles, marks one with hatched lines, and writes '10' (partition size) and '9' (process size) to demonstrate internal fragmentation.

  4. 10:00 – 10:39 10:00-10:39

    The video concludes with the instructor summarizing the concepts. The slide briefly reverts to the 'First fit policy' content, reinforcing the initial topic. The instructor gestures with his hands, wrapping up the lecture on memory allocation strategies and ensuring students understand the distinction between variable and fixed partitioning methods.

The lecture systematically builds understanding of memory management by contrasting dynamic and static allocation strategies. It starts with a specific algorithm (First Fit), moves to the broader concept of variable partitioning with visual examples of memory fragmentation, and concludes with fixed partitioning and its inherent inefficiency (internal fragmentation). The use of analogies (tables) and hand-drawn diagrams reinforces the theoretical concepts, providing a clear visual progression from simple definitions to complex allocation scenarios.

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