Paging vs. Segmentation in Memory Management: A Detailed Comparison
Explore the key differences between paging and segmentation, two fundamental memory management techniques. This comparison clarifies their approaches to dividing a program's address space (fixed-size pages vs. variable-size segments), allocation methods, and how they address the challenges of managing memory in operating systems.
Paging vs. Segmentation: Key Differences in Memory Management
Understanding Paging and Segmentation
Paging and segmentation are both memory management techniques that allow programs larger than available physical memory to run. However, they differ significantly in how they divide the program's address space and manage memory allocation.
Key Differences: Paging vs. Segmentation
| Feature | Paging | Segmentation |
|---|---|---|
| Memory Allocation | Non-contiguous | Non-contiguous |
| Program Division | Fixed-size pages | Variable-sized segments |
| Responsibility | Primarily managed by the operating system | Primarily defined by the compiler or programmer |
| Speed | Generally faster | Generally slower |
| Perspective | OS-centric; doesn't directly reflect program structure | User-centric; aligns with program structure |
| Internal Fragmentation | Present (wasted space within a page) | Absent (no wasted space within a segment) |
| External Fragmentation | Absent (memory is divided into fixed-size units) | Present (free space may be scattered in unusable blocks) |
| Logical Address Structure | Page number, page offset | Segment number, segment offset |
| Data Structure | Page table | Segment table |
| Table Entry Contents | Frame number, control bits | Base address, limit, protection bits |