What is the Difference Between Internal and External Fragmentation?

The main difference between internal and external fragmentation lies in how memory is allocated and wasted in each case.

Internal Fragmentation:

Occurs when memory is divided into fixed-size partitions.
Happens when the memory block assigned to a process is larger than the memory required, leaving some portion of the memory unused.
The unused space is within the allocated memory block and cannot be used by another process.
Internal fragmentation can be reduced by effectively assigning the smallest partition that meets the requirements of the process.

External Fragmentation:

Occurs when memory is divided into variable-size partitions based on the size of the process.
Happens when the total free memory is enough for a new process, but it's not contiguous and can't satisfy the request.
The unused spaces are formed between non-contiguous memory fragments, which are too small to serve a new request.
External fragmentation can be addressed by using compaction and paging techniques.

In summary, internal fragmentation is related to the inefficient use of memory within allocated blocks, while external fragmentation is related to the inefficient use of memory due to non-contiguous memory blocks.

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What is the Difference Between Internal and External Fragmentation?

Comparative Table: Internal vs External Fragmentation

Here is a table comparing internal and external fragmentation:

Feature	Internal Fragmentation	External Fragmentation
Definition	Internal fragmentation occurs when memory is split into fixed-sized blocks, and the allotted memory block is larger than the requested memory, resulting in unused space within the allocated block.	External fragmentation occurs when memory is divided into non-contiguous, variable-sized partitions, leading to scattered gaps between allocated blocks and making it challenging to allocate large contiguous blocks of memory or storage.
Occurrence	Internal fragmentation occurs with fixed-size memory allocation, such as paging and fixed partitioning.	External fragmentation occurs with variable-size memory allocation, such as segmentation and dynamic partitioning.
Causes	Internal fragmentation occurs when the size of a process is larger than the memory required.	External fragmentation occurs when the size of a process is smaller than the memory allocated.
Effects	Internal fragmentation results in wasted space within allocated memory blocks.	External fragmentation results in scattered gaps between allocated memory blocks, making it challenging to allocate large contiguous blocks.
Solutions	Effective partition sizing and best-fit block allocation can help reduce internal fragmentation.	Compaction and paging are solutions to external fragmentation.

In summary, internal fragmentation is related to wasted space within allocated memory blocks due to fixed-size allocation, while external fragmentation involves scattered gaps between allocated memory blocks, making it difficult to allocate large contiguous blocks of memory or storage.

Guilherme Mazui

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.