Memory Management MCQs

1. The address generated by the CPU is known as:

a) Physical Address b) Logical Address c) Relative Address d) Absolute Address

Correct Answer: b) Logical Address

Explanation:
The CPU generates logical (virtual) addresses which are then translated to physical addresses by the MMU (Memory Management Unit).

2. The address seen by the memory unit is called:

a) Logical Address b) Physical Address c) Virtual Address d) Offset Address

Correct Answer: b) Physical Address

Explanation:
The memory unit only deals with physical addresses - the actual locations in physical memory where data is stored.

3. The mapping from logical to physical address is done by:

a) Compiler b) Memory Management Unit (MMU) c) CPU d) Operating System

Correct Answer: b) Memory Management Unit (MMU)

Explanation:
The MMU is the hardware component that performs address translation using page tables maintained by the OS.

4. Which of the following is true about logical address space?

a) It is the same as physical address space b) It is larger than physical address space in virtual memory c) It is smaller than physical address space d) It is generated by the memory unit

Correct Answer: b) It is larger than physical address space in virtual memory

Explanation:
Virtual memory systems allow the logical address space to be much larger than physical memory by using disk space as an extension.

5. Swapping is a technique in which:

a) A process is moved from RAM to disk b) A process is moved from disk to RAM c) Both a and b d) None of the above

Correct Answer: c) Both a and b

Explanation:
Swapping involves moving entire processes between main memory and disk (swap space) to free up memory for other processes.

6. The main disadvantage of swapping is:

a) High CPU utilization b) High disk I/O overhead c) Increased logical address space d) Reduced fragmentation

Correct Answer: b) High disk I/O overhead

Explanation:
Swapping requires significant disk I/O operations which are much slower than memory access, causing performance overhead.

7. In swapping, the process must be:

a) Completely idle b) Completely loaded in memory c) Partially loaded in memory d) None of the above

Correct Answer: b) Completely loaded in memory

Explanation:
Traditional swapping requires the entire process to be in memory (or entirely swapped out), unlike paging which allows partial residency.

8. Which of the following is not a swapping technique?

a) Roll-in b) Roll-out c) Demand Paging d) None of the above

Correct Answer: c) Demand Paging

Explanation:
Demand paging is a different memory management technique that loads pages on demand rather than swapping entire processes.

9. In contiguous memory allocation, memory is divided into:

a) Fixed-size blocks b) Variable-size blocks c) Segments d) Pages

Correct Answer: b) Variable-size blocks

Explanation:
Contiguous allocation assigns variable-sized memory blocks to processes based on their requirements.

10. The problem of external fragmentation occurs in:

a) Paging b) Segmentation c) Contiguous Allocation d) Virtual Memory

Correct Answer: c) Contiguous Allocation

Explanation:
External fragmentation occurs when free memory is broken into small, non-contiguous pieces that can't be used for new allocations.

11. Which of the following is used to reduce external fragmentation?

a) Compaction b) Paging c) Segmentation d) All of the above

Correct Answer: a) Compaction

Explanation:
Compaction moves allocated memory blocks together to create larger contiguous free blocks, though it's computationally expensive.

12. The best-fit memory allocation strategy:

a) Allocates the smallest hole that is big enough b) Allocates the largest available hole c) Allocates the first hole that is big enough d) None of the above

Correct Answer: a) Allocates the smallest hole that is big enough

Explanation:
Best-fit searches for the smallest available memory block that can satisfy the request, minimizing wasted space.

13. In paging, the physical memory is divided into fixed-size blocks called:

a) Frames b) Pages c) Segments d) Blocks

Correct Answer: a) Frames

Explanation:
Physical memory is divided into frames, while logical memory is divided into pages of the same size.

14. The logical memory is divided into fixed-size blocks called:

a) Frames b) Pages c) Segments d) Blocks

Correct Answer: b) Pages

Explanation:
The process's view of memory (logical address space) is divided into equal-sized pages that map to physical frames.

15. The mapping between page and frame is stored in:

a) Page Table b) Segment Table c) Frame Table d) TLB

Correct Answer: a) Page Table

Explanation:
The page table maintains the mapping of logical page numbers to physical frame numbers for each process.

16. The main advantage of paging is:

a) No external fragmentation b) No internal fragmentation c) Supports dynamic linking d) All of the above

Correct Answer: a) No external fragmentation

Explanation:
Paging eliminates external fragmentation because any page can be placed in any available frame, though small internal fragmentation may occur.

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