Definition
Fragmentation
Fragmentation is a phenomenon in which memory becomes unusable because it is divided into small, non-contiguous pieces.
Types
Internal Fragmentation
Occurs when memory is allocated in fixed-size blocks. If a process is smaller than its block, remaining space within the block is wasted.
Occurrence: Fixed Partitioning and Paging.
External Fragmentation
Free memory is scattered in small, non-contiguous blocks between allocations. Total free memory may be sufficient, but no single block is large enough.
Occurrence: Dynamic Partitioning and Segmentation.
Solution: Compaction (shuffle memory to join holes) or non-contiguous allocation (paging).