Internal vs external fragmentation in Operating Systems - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Internal Fragmentation

Which of the following best describes internal fragmentation in memory management?

A Memory lost when the system reserves space for the operating system.

B Unused memory space within an allocated block due to fixed block sizes.

C Memory space wasted between allocated blocks due to variable block sizes.

D Memory fragmentation caused by external devices accessing RAM.

💡 Hint

Think about wasted space inside allocated memory blocks.

Internal fragmentation happens when fixed-size memory blocks are allocated, and the process does not use the entire block, leaving some space unused inside the block.

🧠 Conceptual

intermediate

Understanding External Fragmentation

What is external fragmentation in the context of memory allocation?

A Free memory scattered in small blocks between allocated memory chunks.

B Memory fragmentation caused by hardware faults.

C Memory reserved for system processes only.

D Wasted memory space inside allocated blocks.

💡 Hint

Consider how free memory is arranged outside allocated blocks.

External fragmentation occurs when free memory is split into small pieces scattered between allocated blocks, making it hard to allocate large contiguous blocks.

❓ Comparison

advanced

Comparing Internal and External Fragmentation

Which statement correctly compares internal and external fragmentation?

A External fragmentation wastes memory inside allocated blocks; internal fragmentation wastes memory outside allocated blocks.

B Internal fragmentation occurs only in virtual memory; external fragmentation occurs only in physical memory.

C Internal fragmentation wastes memory inside allocated blocks; external fragmentation wastes memory outside allocated blocks.

D Both internal and external fragmentation waste memory inside allocated blocks.

💡 Hint

Think about where the wasted memory is located in each case.

Internal fragmentation is wasted space inside allocated blocks, while external fragmentation is wasted space outside allocated blocks scattered in small free blocks.

🚀 Application

advanced

Identifying Fragmentation Type from Scenario

A system allocates fixed-size memory blocks of 4 KB. A process requests 6 KB, so it gets two blocks (8 KB total). The extra 2 KB in the second block remains unused. What type of fragmentation is this an example of?

A No fragmentation

B External fragmentation

C Both internal and external fragmentation

D Internal fragmentation

💡 Hint

Focus on unused space inside allocated blocks.

The unused 2 KB inside the allocated block is internal fragmentation because it is wasted space inside allocated memory.

❓ Reasoning

expert

Effect of Fragmentation on Memory Allocation

Consider a memory system with many small free blocks scattered between allocated blocks. Which of the following is the most likely consequence?

A Large memory requests may fail despite enough total free memory due to external fragmentation.

B Memory requests always succeed because total free memory is sufficient.

C Internal fragmentation increases as more small blocks are allocated.

D The system automatically merges allocated blocks to reduce fragmentation.

💡 Hint

Think about how scattered free memory affects large allocations.

External fragmentation causes free memory to be split into small pieces, so large requests may fail even if total free memory is enough.