Internal Fragmentation

Internal fragmentation occurs when fixed-sized memory blocks are allocated to processes. If the memory allocated to a process is larger than what the process actually needs, the unused portion of the memory block is wasted. This happens because the memory is divided into fixed-sized partitions, and a process may not use the entire partition. The wasted space within these allocated blocks is what constitutes internal fragmentation[1][2][3].

External Fragmentation

External fragmentation, on the other hand, happens when memory is allocated in variable-sized blocks. As processes are loaded and unloaded from memory, the free memory space becomes fragmented into small, non-contiguous blocks. This can prevent new processes from being allocated memory, even if the total free memory is sufficient, because there isn't a single contiguous block large enough to accommodate them. External fragmentation is a result of dynamic memory allocation methods that leave unusable gaps between allocated memory blocks[4][5][6].

Key Differences

Managing Fragmentation

To manage internal fragmentation, one can use dynamic memory allocation strategies that minimize wasted space. For external fragmentation, techniques like compaction, paging, and segmentation can be employed to better utilize the available memory[3:1][9].

In summary, internal fragmentation is about wasted space within allocated memory blocks due to fixed-size allocation, and external fragmentation is about the inability to use free memory effectively due to its non-contiguous distribution. Both types of fragmentation can lead to inefficient use of memory and can affect system performance.

Also Read


  1. https://byjus.com/gate/difference-between-internal-and-external-fragmentation/ ↩︎ ↩︎

  2. https://www.geeksforgeeks.org/difference-between-internal-and-external-fragmentation/ ↩︎ ↩︎ ↩︎ ↩︎

  3. https://www.geeksforgeeks.org/internal-fragmentation-in-os/ ↩︎ ↩︎

  4. https://byjus.com/gate/external-fragmentation-in-os-notes/ ↩︎ ↩︎

  5. https://www.geeksforgeeks.org/external-fragmentation-in-os/ ↩︎

  6. https://en.wikipedia.org/wiki/Fragmentation_(computing) ↩︎

  7. https://www.javatpoint.com/internal-vs-external-fragmentation ↩︎

  8. https://www.studytonight.com/operating-system/difference-between-internal-and-external-fragmentation ↩︎

  9. https://www.javatpoint.com/fragmentation-in-operating-system ↩︎

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