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Guilherme Mazui

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What is the Difference Between Paging and Segmentation?

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Paging and segmentation are two methods used for memory management in computer systems. They differ in several aspects:

  1. Size of memory units: In paging, the program is divided into fixed-size pages, while in segmentation, the program is divided into variable-size sections.
  2. Responsibility: In paging, the operating system is responsible for managing memory, while in segmentation, the compiler is responsible.
  3. Speed: Paging is generally faster than segmentation in terms of memory access.
  4. Fragmentation: Paging can lead to internal fragmentation, while segmentation can lead to external fragmentation.
  5. Address space: In paging, the user provides a single integer as the address, while in segmentation, there is the availability of many independent address spaces.
  6. Hardware support: Paging is widely available on CPUs and as MMU chips, while segmentation has limited support on some systems.

In summary, paging and segmentation are both used for memory management, but they differ in the size of memory units, who is responsible for managing memory, speed of memory access, fragmentation, address space, and hardware support.

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  • What is the Difference Between Paging and Segmentation?
  • Comparative Table: Paging vs Segmentation

    • Comparative Table: Paging vs Segmentation

    Here is a table comparing the differences between paging and segmentation:

    Feature Paging Segmentation
    Memory Division Fixed-size blocks for both physical and logical memory Variable-sized blocks for logical memory
    Speed Faster Slower
    Fragmentation Internal fragmentation in paging External fragmentation in segmentation
    Address Space One-dimensional address space Many independent address spaces
    Hardware Support Less hardware support More hardware support
    Sharing of Procedures Does not facilitate sharing Allows for sharing
    Security Fails to distinguish and secure procedures and data separately Can separate secure procedures and data
    Page/Segment Size Fixed block size Variable size
    Main Memory Division Divides main memory into small fixed-size blocks called frames Divides main memory into variable-sized segments
    Secondary Memory Division Divides secondary memory into fixed-size partitions called pages Divides secondary memory into variable-sized partitions called segments
    Page/Segment Table Page table stores page data Segment table stores segment data
    Offset Calculation Processor needs page number and offset to calculate absolute address Processor uses segment number and offset to calculate full address
    User Visibility Invisible to the user Visible to the user
    Frame/Segment Management Operating system maintains a free frame list Operating system maintains a list of holes in the main memory

    In summary, paging uses fixed-size blocks for both physical and logical memory, while segmentation uses variable-sized blocks for logical memory, allowing for more flexibility in memory allocation. Paging is faster compared to segmentation, but it can result in internal fragmentation, while segmentation can result in external fragmentation. Paging is invisible to the user, while segmentation is visible.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.