There are generally three recognized types of fragmentation, depending on the context:
- Internal Fragmentation
This occurs when memory is allocated in fixed-size blocks, but the process or data requires less space than the allocated block, leaving unused space inside the allocated area. This wasted space within allocated memory is called slack space. It is difficult to reclaim without redesigning the memory allocation scheme
- External Fragmentation
External fragmentation happens when free memory is available but scattered in small, non-contiguous blocks, so a process requiring a large contiguous block cannot be allocated even though the total free memory is sufficient. This leads to unusable small holes between allocated memory blocks
- Data Fragmentation (also called sometimes logical fragmentation)
This type refers to fragmentation of data itself, such as in databases or file systems, where data is split into pieces that are not stored contiguously. It can also refer to fragmentation in distributed databases, including horizontal, vertical, and mixed (hybrid) fragmentation, which are ways to partition data for performance and management reasons
In summary, the three main types of fragmentation are internal, external, and data fragmentation. Internal and external fragmentation are common in memory management and operating systems, while data fragmentation is more relevant in databases and distributed systems
