Segmentation and Protection: Memory Management in Operating Systems

Question 1

Which register defines the starting address of a segment?

Accepted Answer

Base register

Answer

Limit register

Answer

Segmentation table

Answer

Protection key

Question 2

Which data structure stores the base and limit values of segments?

Accepted Answer

Segmentation table

Answer

Memory Management Unit (MMU)

Answer

Page table

Answer

Access control list

Question 3

What is the primary purpose of memory segmentation in an operating system?

Accepted Answer

To isolate processes and data

Answer

To improve memory performance

Answer

To enhance security

Answer

To reduce memory fragmentation

Question 4

Which mechanism restricts access to segments based on permissions?

Accepted Answer

Access control lists

Answer

Paging

Answer

Virtualization

Answer

Segmentation

Question 5

What occurs when a process attempts to access a memory location outside its assigned segment?

Accepted Answer

The operating system generates a segmentation fault

Answer

The process is terminated

Answer

The data is loaded from the disk into memory

Answer

The access is granted if the process has enough privileges

Question 6

What is the distinction between intra-segment and inter-segment references?

Accepted Answer

Intra-segment references occur within the same segment, while inter-segment references cross segment boundaries

Answer

Inter-segment references are faster than intra-segment references

Answer

Intra-segment references require access control checks, while inter-segment references do not

Answer

There is no difference between intra-segment and inter-segment references

Question 7

How does memory segmentation help protect the operating system from user processes?

Accepted Answer

It isolates the operating system's memory from user processes

Answer

It encrypts the operating system's memory

Answer

It runs the operating system in a separate processor

Answer

It gives the operating system higher priority than user processes

Question 8

In a segmented memory architecture, which component provides the mapping between a logical address and a physical address?

Accepted Answer

Segmentation table

Answer

Paging table

Answer

Translation lookaside buffer

Answer

Memory management unit

Question 9

What is the term for the technique of dividing memory into fixed-size blocks called pages?

Accepted Answer

Paging

Answer

Segmentation

Answer

Virtualization

Answer

Swapping

Question 10

Which type of memory allocation strategy allocates a continuous block of memory to a process?

Accepted Answer

Static allocation

Answer

Dynamic allocation

Answer

Buddy allocation

Answer

Slab allocator

Question 11

How does segmentation enhance efficient memory utilization in an operating system?

Accepted Answer

It eliminates memory fragmentation by allocating space only to processes that need it.

Answer

It reduces the overhead associated with address translation.

Answer

It improves the performance of cache memory.

Question 12

How does segmentation facilitate the implementation of virtual memory?

Accepted Answer

Segmentation divides memory into segments of varying sizes.

Answer

Segmentation uses base and limit registers to track memory usage.

Answer

Segmentation protects memory areas from unauthorized access.

Answer

Segmentation allows multiple processes to share the same physical memory space.

Question 13

Which register holds the starting address of the currently active segment?

Accepted Answer

Base register

Answer

Data register

Answer

Index register

Answer

Program counter

Question 14

What is the primary purpose of a segmentation table?

Accepted Answer

To store the base and limit addresses of segments, allowing the processor to locate them in memory

Answer

To keep track of which segments are currently being used by processes

Answer

To protect memory from unauthorized access by enforcing access permissions

Answer

To improve the speed of memory access by caching frequently used segments

Question 15

Which mechanism is responsible for preventing processes from accessing memory outside their allocated segments?

Accepted Answer

Base and limit registers

Answer

Page tables

Answer

Access control lists

Answer

Virtual memory

Question 16

How do logical addresses differ from physical addresses?

Accepted Answer

Logical addresses are relative to the segment, while physical addresses are absolute memory locations.

Answer

Physical addresses are relative to the segment, while logical addresses are absolute memory locations.

Answer

Logical addresses are used by the operating system, while physical addresses are used by the hardware.

Answer

Physical addresses are used by the operating system, while logical addresses are used by the hardware.

Question 17

Which of the following is not an advantage of memory segmentation?

Accepted Answer

Faster memory access

Answer

Enhanced memory protection

Answer

Improved memory efficiency

Answer

Simplified memory management

Question 18

What is the main purpose of a segmentation table?

Accepted Answer

To map logical segment addresses to physical memory addresses

Answer

To manage page faults

Answer

To enforce access control

Answer

To schedule processes

Question 19

Which of the following is NOT a potential benefit of memory segmentation?

Accepted Answer

Guaranteed performance improvements

Answer

Isolation of processes

Answer

Protection of memory

Answer

Enhanced security

Question 20

Which access control mechanism allows specific users or groups to access certain memory segments?

Accepted Answer

Access control list

Answer

Capability list

Answer

Role-based access control

Answer

Mandatory access control

Question 21

What is the fundamental difference between a segment and a page in memory management?

Accepted Answer

Pages are fixed-size while segments are variable-size

Answer

Segments are fixed-size while pages are variable-size

Answer

Segments are managed entirely by the hardware while pages are managed by the operating system

Answer

Pages are managed entirely by the hardware while segments are managed by the operating system

Question 22

What is the primary purpose of a limit register in memory protection?

Accepted Answer

To define the maximum allowable size of a segment

Answer

To store the current location of the instruction pointer

Answer

To track the number of page faults that have occurred

Answer

To enforce access permissions

Question 23

What is a key advantage of using segmentation over flat memory architectures?

Accepted Answer

Improved security through isolation and access control

Answer

Guaranteed performance enhancements for all applications

Answer

Reduced complexity in memory management

Answer

Elimination of memory fragmentation

Question 24

Which register pair stores the base address and limit for a specific segment?

Accepted Answer

Base register and Limit register

Answer

Code segment register (CS) and Data segment register (DS)

Answer

Source register and Destination register

Answer

Stack pointer and Base pointer

Question 25

The table that maps logical segment addresses to physical memory addresses is called:

Accepted Answer

Segmentation table

Answer

Translation Lookaside Buffer (TLB)

Answer

Page table

Answer

Directory table

Question 26

Which of the following is NOT a protection mechanism used in segmentation?

Accepted Answer

Ring protection

Answer

Access control lists (ACLs)

Answer

Bounds checking

Answer

Base and limit registers

Question 27

The technique of dividing memory into variable-sized blocks to manage memory more efficiently is called:

Accepted Answer

Segmentation

Answer

Paging

Answer

Virtual memory

Answer

Address translation

Question 28

In a protected memory system, processes are assigned to isolated:

Accepted Answer

Segments

Answer

Pages

Answer

Rings

Answer

Levels

Question 29

Which of the following is the primary function of a base register in segmentation?

Accepted Answer

Stores the starting physical address of a segment

Answer

Stores the ending physical address of a segment

Answer

Determines the maximum size of a segment

Answer

Enforces access permissions and protections

Question 30

Which of the following is NOT a characteristic of segmented memory allocation?

Accepted Answer

Segments are always contiguous in physical memory

Answer

Segments have variable sizes and can grow dynamically

Answer

Segments can overlap and share memory space

Answer

Segments can be easily protected and isolated

Question 31

In a segmentation system, which component is responsible for managing and translating segment addresses?

Accepted Answer

Memory management unit (MMU)

Answer

Operating system

Answer

Base register

Answer

Limit register

Question 32

What is the typical response from an operating system when a program tries to access memory beyond its allocated segment?

Accepted Answer

Terminating the program

Answer

Restarting the computer

Answer

Displaying a warning message

Question 33

In a segmentation-based memory protection scheme, which mechanism ensures that memory accesses are restricted to within the defined boundaries of a segment?

Accepted Answer

Bounds checking

Answer

Segmentation tables

Answer

Access control lists

Answer

Hardware-enforced access rights

Question 34

What is the role of the limit register?

Accepted Answer

Defines the maximum size of a segment

Answer

Stores the physical address of a segment

Answer

Controls access to a segment

Answer

Maps virtual addresses to physical addresses

Question 35

Which data structure stores information about the size and location of each segment?

Accepted Answer

Segmentation table

Answer

Page table

Answer

File allocation table

Answer

Descriptor table

Question 36

What is the fundamental distinction between segmentation and paging?

Accepted Answer

Segmentation divides memory into variable-sized segments, while paging divides it into fixed-sized pages

Answer

Paging provides better memory utilization than segmentation

Answer

Segmentation is more efficient than paging for large processes

Answer

Paging requires hardware support, while segmentation does not

Question 37

Which type of access control list allows permissions to be set for particular processes?

Accepted Answer

Discretionary access control list (DACL)

Answer

System access control list (SACL)

Answer

Mandatory access control list (MACL)

Answer

Role-based access control list (RBACL)

Question 38

What is the primary advantage of implementing memory protection mechanisms?

Accepted Answer

Preventing unauthorized memory access

Answer

Improving memory performance

Answer

Reducing memory fragmentation

Answer

Increasing system stability

Question 39

Which hardware component is typically utilized to implement the base and limit registers?

Accepted Answer

Memory management unit (MMU)

Answer

Central processing unit (CPU)

Answer

Input/output controller (IOC)

Answer

Direct memory access (DMA) controller

Question 40

Which operating system employs a pure segmentation approach for memory management?

Accepted Answer

OpenVMS

Answer

Windows

Answer

Linux

Answer

Unix

Question 41

How do internal and external fragmentation impact the efficiency of memory segmentation?

Accepted Answer

Internal fragmentation: excess memory allocated to segments, resulting in unused space within segments.

Accepted Answer

External fragmentation: unallocated memory spread throughout memory, resulting in unusable memory gaps.

Answer

Internal fragmentation: unused memory scattered throughout memory, reducing memory usage.

Answer

External fragmentation: reduces memory usage by allocating excess memory to segments.

Question 42

Which register pair holds the addresses indicating the start and end of a memory segment?

Accepted Answer

Base and Limit

Answer

Index and Offset

Answer

Pointer and Size

Answer

Segment and Table

Question 43

Which of the following is NOT a potential advantage of memory segmentation?

Accepted Answer

Increased program execution speed

Answer

Enhanced memory protection

Answer

Reduced memory fragmentation

Answer

Simplified memory management

Question 44

What is the function of an access control list (ACL) in memory protection?

Accepted Answer

To specify read, write, and execute permissions for each segment

Answer

To define which processes can access a specific memory segment

Answer

To monitor changes made to memory segments

Answer

To ensure that memory segmentation boundaries are maintained

Question 45

In a segmented memory system, what occurs when a process tries to access memory beyond its assigned segment?

Accepted Answer

An interrupt is generated by the operating system

Answer

The process is terminated

Answer

Data is automatically retrieved from another segment

Answer

No action is taken, as the process has access to all segments

Question 46

Which of the following is a potential disadvantage of memory segmentation?

Accepted Answer

Internal fragmentation

Answer

Increased memory overhead

Answer

Limited address space

Answer

Slow memory access

Question 47

What is the primary distinction between segmentation and paging?

Accepted Answer

Segmentation divides memory into fixed-size segments, while paging uses equal-size pages

Answer

Segmentation is hardware-based, while paging is software-based

Answer

Paging offers better memory protection than segmentation

Answer

Segmentation is used in modern OSes, while paging is outdated

Question 48

How does segmentation contribute to memory isolation?

Accepted Answer

By assigning separate segments to different processes, preventing them from accessing each other's memory

Answer

By using access control lists to grant or deny access to specific segments

Answer

By creating a virtual memory space that isolates processes

Answer

By encrypting data in memory segments to protect it from unauthorized access

Question 49

Which of the following is NOT an advantage of memory segmentation?

Accepted Answer

Eliminates the need for a memory management unit (MMU)

Answer

Provides isolation for processes, preventing them from accessing each other's memory

Answer

Simplifies memory management by organizing memory into logical and manageable units

Question 50

What is the purpose of a base register in segmentation?

Accepted Answer

Stores the starting physical address of a segment

Answer

Tracks the current position within a segment

Answer

Protects a segment from unauthorized access

Answer

Stores the size of a segment

Question 51

Which of the following is NOT a benefit of using access control lists (ACLs) for memory protection?

Accepted Answer

Simplifies the implementation of memory protection

Answer

Provides flexibility in setting different levels of access for different entities

Answer

Allows fine-grained control over which users and processes can access specific areas of memory

Question 52

What is the role of paging in memory protection?

Accepted Answer

Divides memory into fixed-size pages and enforces access restrictions on each page

Answer

Partitions memory into variable-sized segments

Answer

Tracks the location of segments in memory

Question 53

What is the difference between logical and physical addresses in segmentation?

Accepted Answer

Logical addresses are relative to the start of a segment, while physical addresses are relative to the start of physical memory

Answer

Logical addresses are larger than physical addresses

Question 54

What is the purpose of a memory management unit (MMU) in segmentation?

Accepted Answer

Translates logical addresses generated by the CPU into physical addresses that can be used by memory

Answer

Enforces access control for memory

Answer

Creates and manages segments

Answer

Protects processes from each other

Question 55

Which of the following is NOT a type of segmentation protection?

Accepted Answer

Heap protection

Answer

Base and limit registers

Answer

Bounds checking

Answer

Access control lists

Question 56

What is the main difference between segmentation and paging?

Accepted Answer

Segmentation divides memory into variable-sized segments, while paging divides memory into fixed-size pages

Answer

Segmentation is implemented in hardware, while paging is implemented in software