Contiguous Allocation Policy and Address Translation

Duration: 9 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.

This educational video lecture provides a detailed explanation of the contiguous allocation policy used in operating systems for memory management. The instructor begins by defining the policy, emphasizing that a process must be loaded entirely into main memory and stored in a contiguous block of addresses. He illustrates the data flow between the CPU, main memory, and secondary memory using hand-drawn diagrams. The lecture then explores the implications of this policy, specifically how processes are allocated within memory partitions and the constraints imposed by non-contiguous free space. Finally, the instructor introduces the Memory Management Unit (MMU) and the relocation register, explaining the mechanism of translating logical addresses to physical addresses by adding a base address to the logical address generated by the CPU.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a slide titled 'Contiguous allocation policy'. The instructor explains that when a process is executed, it must be loaded into main memory. He lists two key implications visible on the slide: 'It must be loaded to main memory completely for execution' and 'Must be stored in main memory in contiguous fashion'. To visualize this, he draws a diagram showing a box labeled 'CPU' pointing to 'M.M' (Main Memory), which in turn interacts with 'S.M' (Secondary Memory). He explains that the CPU generates logical addresses which are then translated into physical addresses in main memory.

  2. 2:00 – 5:00 02:00-05:00

    The instructor elaborates on the 'contiguous fashion' requirement. He draws a representation of main memory divided into partitions. He presents a scenario where a process of size 50 needs to be loaded. He draws available memory blocks of size 30 and 40. He explains that even though the total free space (30 + 40 = 70) is greater than the process size (50), the process cannot be loaded because the free space is not contiguous. This demonstrates the fragmentation issue inherent in contiguous allocation, where a process requires a single continuous block of memory.

  3. 5:00 – 8:52 05:00-08:52

    The lecture transitions to the hardware mechanism used to manage these addresses. A slide appears stating, 'Here we use a memory management unit(OS) whose duty is to take logical address and translate it into physical address.' The instructor draws a diagram of the MMU containing a 'relocation register' and an adder. He explains that the relocation register holds the base address of the process in main memory. He provides a numerical example: if the CPU generates a logical address of 42 and the base address in the relocation register is 100, the adder sums them to produce a physical address of 142. He also briefly mentions the advantage (simple strategy) and disadvantage (security risk if logical address exceeds limit) of this method.

The lecture systematically builds the concept of contiguous allocation, starting from the fundamental requirement that processes must reside in continuous memory blocks. It then demonstrates the practical limitations of this approach through memory partition examples, highlighting the inability to utilize fragmented free space. The lesson concludes by introducing the MMU and relocation register as the essential hardware components that enable this policy by mapping logical addresses to physical addresses, ensuring processes run in their allocated memory regions.

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