Paging: An Efficient Memory Management Technique

1. How Paging Works

Paging divides both logical memory (process memory) and physical memory (RAM) into fixed-size units:


Pages: Fixed-size blocks of a program’s memory space.

Page Frames: Corresponding fixed-size blocks in physical RAM where pages are loaded.

When a process is executed, its pages are mapped to available page frames in RAM. If a required page is not in RAM, a page fault occurs, prompting the OS to load it from disk.


2. Key Components of Paging

Page Table: A mapping structure that links logical pages to physical page frames.

Frame Number: Identifies where a page is stored in physical memory.

Page Offset: Specifies the exact location of data within a page.


3. Advantages of Paging

- Prevents External Fragmentation: Fixed-size pages eliminate gaps in memory allocation.

- Optimized Memory Utilization: Processes can use non-contiguous frames, reducing wasted space.

- Supports Virtual Memory: Pages can be temporarily stored on disk, allowing programs to use more memory than physically available.

- Simplifies Memory Management: The OS handles memory in fixed-size blocks, making allocation and deallocation more efficient.


4. Disadvantages of Paging

- Overhead from Page Tables: The OS must manage page tables for each process, increasing memory usage.

- Performance Impact from Page Faults: Retrieving pages from disk slows execution when frequent page faults occur.

- TLB Misses: If a requested page is not found in the Translation Lookaside Buffer (TLB), additional memory lookups increase access time.


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