1. What is a cache miss?
(A) When the requested data is not found in the cache and must be fetched from main memory
(B) When the requested data is found in the cache and is immediately used
(C) When data is incorrectly stored in the cache
(D) When the cache size is exceeded
2. What occurs during a cache hit?
(A) The cache must fetch the data from main memory
(B) The requested data is found in the cache and can be accessed quickly
(C) The data is written to the cache
(D) The cache size is increased
3. Which of the following can lead to a higher cache miss rate?
(A) Larger cache size
(B) Improved cache associativity
(C) Frequent access to data not present in the cache
(D) Larger cache line size
4. How does increasing the cache size generally affect the cache miss rate?
(A) It typically reduces the cache miss rate
(B) It increases the cache miss rate
(C) It has no effect on the cache miss rate
(D) It increases the frequency of cache hits
5. What is the impact of a cache hit on system performance?
(A) It causes a delay in data retrieval
(B) It degrades performance due to increased cache management overhead
(C) It has no impact on performance
(D) It improves performance by reducing the time needed to access data
6. What typically happens when a cache miss occurs?
(A) The system writes data to the cache
(B) The system must fetch the data from main memory or another lower-level cache
(C) The system increases the cache size
(D) The cache is cleared
7. Which factor does not influence the cache miss rate?
(A) Cache size
(B) Cache associativity
(C) Cache replacement policy
(D) CPU clock speed
8. What is the effect of a higher cache associativity on cache performance?
(A) It generally reduces the cache miss rate
(B) It increases the cache miss rate
(C) It has no effect on cache miss rate
(D) It speeds up the CPU clock
9. What is the primary goal of a cache replacement policy?
(A) To improve the speed of the CPU
(B) To increase the size of the cache
(C) To decide which cache line to replace when a cache miss occurs
(D) To reduce the power consumption of the cache
10. Which of the following is a common cache replacement policy?
(A) Direct-mapped
(B) Write-through
(C) Write-back
(D) Least Recently Used (LRU)
11. What does a high cache miss rate indicate about a system?
(A) The system may have inadequate cache size or poor cache utilization
(B) The system has optimal cache performance
(C) The cache size is too large
(D) The cache replacement policy is perfect
12. Which cache mapping technique typically results in a higher cache miss rate?
(A) Fully associative
(B) Set-associative
(C) Direct-mapped
(D) Random
13. What is the effect of increasing the cache line size?
(A) It decreases the hit rate
(B) It increases the number of cache misses
(C) It has no impact on cache performance
(D) It can reduce the cache miss rate by fetching more contiguous data
14. Which of the following strategies is likely to decrease the number of cache misses?
(A) Increasing cache associativity
(B) Reducing cache size
(C) Using a direct-mapped cache
(D) Implementing a more aggressive replacement policy
15. What is a consequence of a cache miss in a system with multiple cache levels?
(A) The system immediately retrieves data from the cache
(B) The system may need to fetch data from a lower-level cache or main memory
(C) The system increases the cache size
(D) The cache is reset
16. Which of the following is a characteristic of a direct-mapped cache?
(A) Cache lines are chosen randomly
(B) Each block of memory can map to multiple cache lines
(C) Each block of memory maps to exactly one cache line
(D) There is no mapping between memory blocks and cache lines
17. In which cache configuration is the likelihood of a cache miss generally the highest?
(A) Direct-mapped cache
(B) Fully associative cache
(C) Set-associative cache
(D) Multi-level cache
18. What is the advantage of a set-associative cache over a direct-mapped cache?
(A) It speeds up data retrieval from main memory
(B) It increases the cache size
(C) It simplifies cache management
(D) It reduces the likelihood of cache collisions and thus reduces the miss rate
19. What is a cache miss rate?
(A) The total number of cache lines
(B) The fraction of cache accesses that result in a hit
(C) The fraction of memory accesses that result in a cache miss
(D) The speed of the cache
20. How does the cache size typically influence the cache hit rate?
(A) A larger cache size decreases the cache hit rate
(B) A larger cache size generally increases the cache hit rate
(C) Cache size does not affect the cache hit rate
(D) Cache size affects only the cache miss rate
21. What is the primary benefit of reducing the cache miss rate?
(A) It increases the cache line size
(B) It increases the complexity of the cache design
(C) It reduces the cache size
(D) It improves overall system performance by reducing the time spent fetching data from main memory
22. What is a “compulsory miss”?
(A) A cache miss caused by a cache line eviction
(B) A cache miss that occurs when data is accessed for the first time
(C) A cache miss due to a conflict in the cache
(D) A cache miss caused by a faulty cache line
23. What is a “conflict miss”?
(A) A cache miss that occurs due to multiple blocks mapping to the same cache line in a direct-mapped cache
(B) A cache miss caused by a cache line eviction
(C) A cache miss due to data being accessed for the first time
(D) A cache miss caused by an invalid cache entry
24. What is a “capacity miss”?
(A) A cache miss due to the data being accessed for the first time
(B) A cache miss caused by a conflict in the cache
(C) A cache miss that occurs when the cache cannot hold all the blocks needed for a program’s execution
(D) A cache miss caused by a faulty cache line
25. What strategy can help reduce the impact of compulsory misses?
(A) Using a more aggressive replacement policy
(B) Increasing cache size
(C) Increasing cache associativity
(D) Implementing a prefetching mechanism to load data into the cache before it is requested
26. Which cache replacement policy would help reduce the number of conflict misses?
(A) Least Recently Used (LRU)
(B) First In, First Out (FIFO)
(C) Random Replacement
(D) Write-back
27. What is the effect of a larger cache line size on cache misses?
(A) It increases the frequency of conflict misses
(B) It can reduce the number of compulsory and capacity misses by fetching more contiguous data
(C) It has no effect on cache miss rate
(D) It reduces the overall cache size
28. Which type of cache miss is least affected by increasing cache size?
(A) Conflict miss
(B) Compulsory miss
(C) Capacity miss
(D) All types are equally affected
29. What is a primary benefit of increasing the cache associativity in terms of cache misses?
(A) It increases compulsory misses
(B) It reduces conflict misses by allowing multiple blocks to map to the same cache line
(C) It has no effect on cache misses
(D) It increases the number of capacity misses
30. In which scenario is a “write-allocate” policy most useful?
(A) When data is only read from the cache
(B) When data is written directly to the main memory without affecting the cache
(C) When a cache miss occurs on a write operation and the cache line is loaded from main memory
(D) When the cache is being cleared
31. What is the effect of cache line replacement on cache misses?
(A) It automatically reduces cache size
(B) It decreases the number of cache misses
(C) It has no impact on cache misses
(D) It can potentially increase the number of conflict misses if the replaced line is frequently accessed
32. How does a larger cache typically impact the time taken to resolve a cache miss?
(A) It can reduce the time taken to resolve a miss by increasing the likelihood of data being present in the cache
(B) It increases the time taken to resolve a miss
(C) It has no effect on the time taken to resolve a miss
(D) It speeds up data retrieval from main memory
33. What is the impact of cache hit latency on overall system performance?
(A) Higher hit latency improves system performance
(B) Lower hit latency improves system performance by reducing the time needed to access data from the cache
(C) Cache hit latency does not affect system performance
(D) It increases the number of cache misses
34. How does a cache’s replacement policy affect cache hit rate?
(A) It only affects cache miss rate
(B) It has no impact on the cache hit rate
(C) It can influence the likelihood of retaining frequently accessed data, thereby affecting the hit rate
(D) It reduces cache hit rate by increasing replacement frequency
35. What is a common cause of a “cold miss” or “compulsory miss”?
(A) Accessing data that was evicted due to cache size limitations
(B) Accessing data that is not in the cache due to replacement
(C) Accessing data that was recently written to the cache
(D) Accessing data for the first time that has not been previously loaded into the cache
36. What role does prefetching play in cache performance?
(A) It increases the number of cache misses
(B) It helps reduce cache misses by loading data into the cache before it is requested
(C) It clears the cache periodically
(D) It changes the cache replacement policy
37. How does a “write-around” policy affect cache misses compared to a “write-allocate” policy?
(A) Write-around policy increases cache hits by keeping data out of the cache
(B) Write-allocate policy reduces cache misses on write operations by loading data into the cache
(C) Write-around can increase cache misses on write operations by not loading the data into the cache
(D) Both policies have no impact on cache misses
38. Which type of cache miss is less frequent in a well-designed caching system?
(A) Capacity miss
(B) Compulsory miss
(C) Conflict miss
(D) All types are equally frequent
39. What is the primary purpose of a cache?
(A) To speed up data access by storing frequently used data closer to the CPU
(B) To increase the size of the main memory
(C) To reduce the overall power consumption of the system
(D) To replace main memory entirely
40. How can increasing the number of cache sets in a set-associative cache impact cache performance?
(A) It decreases the cache size
(B) It increases the likelihood of cache misses
(C) It has no effect on cache performance
(D) It can reduce the number of conflict misses by allowing more flexibility in data mapping
41. What is the main benefit of using a fully associative cache compared to a direct-mapped cache?
(A) It reduces the number of conflict misses by allowing any block to be placed in any cache line
(B) It simplifies cache management
(C) It reduces the cache size
(D) It increases the number of compulsory misses
42. How does a direct-mapped cache handle cache line replacement?
(A) It randomly selects a cache line to replace
(B) It replaces the cache line corresponding to a specific index when a new block maps to that index
(C) It replaces the least recently used cache line
(D) It replaces the cache line with the most recent access
43. What impact does a high number of cache sets have on cache performance in a set-associative cache?
(A) It has no effect on cache performance
(B) It increases the number of conflict misses
(C) It generally reduces the number of conflict misses and improves performance
(D) It decreases cache size
44. Which of the following is most likely to improve cache performance for sequential access patterns?
(A) Using a direct-mapped cache
(B) Reducing cache size
(C) Decreasing cache associativity
(D) Increasing cache line size
45. How does the cache line size impact the handling of spatial locality?
(A) Larger cache lines can better exploit spatial locality by fetching contiguous data in one operation
(B) Smaller cache lines are better for spatial locality
(C) Cache line size does not affect spatial locality
(D) Larger cache lines decrease the effectiveness of spatial locality
46. What is a “miss rate” in the context of cache performance?
(A) The percentage of cache accesses that result in a hit
(B) The percentage of memory accesses that result in a cache miss
(C) The total number of cache lines
(D) The speed at which data is accessed from the cache
47. What factor is least likely to affect cache hit rate?
(A) Cache size
(B) Cache associativity
(C) Cache line size
(D) CPU temperature
48. What is the most effective way to reduce the number of capacity misses?
(A) Increasing the cache size to accommodate more data
(B) Reducing cache line size
(C) Increasing the associativity of the cache
(D) Using a write-back policy
49. How does the use of prefetching affect cache miss rates?
(A) It increases cache miss rates
(B) It can reduce cache miss rates by loading data into the cache before it is accessed
(C) It has no impact on cache miss rates
(D) It causes data to be discarded from the cache
50. What type of cache miss occurs when a program accesses data for the first time?
(A) Conflict miss
(B) Capacity miss
(C) Compulsory miss
(D) Coherence miss
51. Which type of I/O operation involves the CPU being actively involved in the transfer process?
(A) Memory-mapped I/O
(B) Direct Memory Access (DMA)
(C) Interrupt-driven I/O
(D) Programmed I/O
52. What is Direct Memory Access (DMA) used for in I/O operations?
(A) To allow peripheral devices to access memory directly without CPU intervention
(B) To convert analog signals to digital
(C) To manage CPU cache
(D) To handle arithmetic operations
53. In the context of I/O operations, what does “polling” refer to?
(A) A method for converting digital data to analog
(B) The CPU repeatedly checks the status of an I/O device to determine if it is ready for data transfer
(C) The process of buffering data
(D) The execution of I/O commands by DMA
54. Which I/O method allows the CPU to be interrupted when an I/O device needs attention?
(A) Direct Memory Access (DMA)
(B) Programmed I/O
(C) Interrupt-driven I/O
(D) Memory-mapped I/O
55. What is the main advantage of using Direct Memory Access (DMA) over programmed I/O?
(A) DMA reduces CPU involvement in data transfer, allowing for more efficient processing
(B) DMA requires more CPU cycles for data transfer
(C) DMA increases the number of interrupts required
(D) DMA simplifies the buffer management process
56. Which of the following describes memory-mapped I/O?
(A) I/O devices are directly connected to the CPU’s registers
(B) I/O devices are accessed through separate I/O instructions
(C) I/O operations are handled through interrupt signals
(D) I/O devices are accessed using the same address space as memory
57. What is an interrupt vector?
(A) A table used to manage and handle interrupts in a computer system
(B) A type of I/O buffer
(C) A hardware component for converting digital signals
(D) A method for direct memory access
58. Which I/O technique involves the use of interrupts to signal the CPU that an I/O operation is complete?
(A) Programmed I/O
(B) Interrupt-driven I/O
(C) Direct Memory Access (DMA)
(D) Memory-mapped I/O
59. What is the function of a device driver in an I/O system?
(A) To manage CPU registers
(B) To directly access memory locations
(C) To provide a software interface between the operating system and hardware devices
(D) To convert analog signals to digital
60. Which of the following is a characteristic of programmed I/O?
(A) Data transfer is managed by DMA controllers
(B) I/O devices access memory directly without CPU intervention
(C) The CPU is interrupted for every I/O operation
(D) The CPU directly controls data transfer operations and waits for I/O operations to complete
61. How does an interrupt improve system efficiency during I/O operations?
(A) It allows the CPU to perform other tasks while waiting for I/O operations to complete
(B) It increases the time required for data transfer
(C) It directly accesses memory without the need for CPU intervention
(D) It reduces the need for buffering data
62. What is the primary purpose of an I/O controller?
(A) To perform arithmetic operations
(B) To manage communication between the CPU and peripheral devices
(C) To handle data storage
(D) To execute software instructions
63. Which I/O technique is characterized by the CPU issuing commands to the I/O device and waiting for the device to complete the operation?
(A) Interrupt-driven I/O
(B) Direct Memory Access (DMA)
(C) Programmed I/O
(D) Memory-mapped I/O
64. What role does the system bus play in I/O operations?
(A) It converts digital signals to analog
(B) It directly controls the execution of instructions
(C) It manages memory allocation
(D) It facilitates data transfer between the CPU, memory, and I/O devices
65. In an interrupt-driven I/O system, what happens when an interrupt occurs?
(A) The I/O device immediately writes data to memory
(B) The CPU stops its current task and executes an interrupt service routine to handle the I/O operation
(C) The CPU continues its current task without interruption
(D) The I/O device requests additional data from the CPU
66. What is the purpose of an I/O port in a computer system?
(A) To execute computational tasks
(B) To store data temporarily
(C) To provide a physical or logical interface for connecting I/O devices to the system
(D) To convert analog signals to digital
67. Which I/O method allows devices to be mapped into the address space of the CPU, allowing for direct memory access?
(A) Programmed I/O
(B) Direct Memory Access (DMA)
(C) Interrupt-driven I/O
(D) Memory-mapped I/O
68. What does a “buffer overflow” error indicate?
(A) Data exceeds the capacity of the buffer, leading to potential data loss or corruption
(B) The buffer is empty and no data is available
(C) The buffer is full and cannot accept additional data
(D) Data is incorrectly formatted for the buffer
69. What is the primary function of a bus controller in an I/O system?
(A) To convert digital signals
(B) To execute data transfer commands from the CPU
(C) To perform arithmetic operations
(D) To manage and control the flow of data on the system bus
70. How does an I/O operation affect CPU performance in a programmatic I/O environment?
(A) The CPU must wait for I/O operations to complete, potentially reducing overall performance
(B) I/O operations have no effect on CPU performance
(C) The CPU executes I/O operations concurrently with other tasks
(D) I/O operations speed up CPU performance
71. What is the purpose of an interrupt service routine (ISR)?
(A) To manage memory allocation
(B) To handle specific tasks related to interrupts and I/O operations
(C) To perform arithmetic calculations
(D) To execute data transfer commands
72. In which situation is Direct Memory Access (DMA) most beneficial?
(A) When the CPU must be directly involved in every data transfer operation
(B) When minimal data transfer is required
(C) When large amounts of data need to be transferred between I/O devices and memory without CPU involvement
(D) When I/O operations are infrequent
73. What is a key characteristic of an interrupt-driven I/O system?
(A) The CPU is notified via interrupts when an I/O device needs attention
(B) The CPU must poll the device constantly to check for data readiness
(C) Data is transferred directly to memory without CPU intervention
(D) The I/O device directly accesses CPU registers
74. Which component is responsible for translating I/O requests into electrical signals that can be understood by the device?
(A) CPU
(B) Memory unit
(C) I/O controller
(D) System bus
75. What does the term “polling” imply in the context of I/O systems?
(A) The system automatically buffers incoming data
(B) The CPU interrupts the device to request data
(C) The device directly accesses memory
(D) The CPU regularly checks the status of an I/O device to determine if it is ready for data transfer
76. How does an I/O device use interrupts to signal the CPU?
(A) The device writes data directly to memory without involving the CPU
(B) The device sends an interrupt signal to the CPU, which pauses its current task to handle the I/O operation
(C) The CPU continuously polls the device to check for status changes
(D) The device initiates DMA operations
77. What is the primary advantage of using DMA over interrupt-driven I/O?
(A) DMA allows for more efficient data transfer without constant CPU intervention
(B) DMA requires more CPU cycles to manage I/O operations
(C) DMA increases the number of interrupts required
(D) DMA simplifies the buffer management process
78. What is an example of an I/O device that typically uses direct memory access (DMA)?
(A) Keyboards
(B) Disk drives
(C) Mice
(D) Printers
79. In which I/O method does the CPU perform read and write operations directly to and from the I/O device?
(A) Interrupt-driven I/O
(B) Direct Memory Access (DMA)
(C) Programmed I/O
(D) Memory-mapped I/O
80. What does a “hardware interrupt” refer to?
(A) A type of data conversion process
(B) A software command that suspends current operations
(C) A method for managing memory allocation
(D) A signal generated by hardware to alert the CPU to an event that needs immediate attention
81. Which I/O technique involves the CPU waiting for an I/O operation to complete before continuing with other tasks?
(A) Programmed I/O
(B) Interrupt-driven I/O
(C) Direct Memory Access (DMA)
(D) Memory-mapped I/O
82. How does a memory-mapped I/O system simplify the communication between the CPU and I/O devices?
(A) By isolating I/O operations from memory operations
(B) By using the same address space for both memory and I/O devices, simplifying access
(C) By using dedicated I/O instructions
(D) By directly accessing CPU registers
83. What is the function of an I/O bus in a computer system?
(A) To execute arithmetic calculations
(B) To manage data storage
(C) To provide a communication pathway between the CPU, memory, and I/O devices
(D) To control the operating system
84. What does the term “buffering” refer to in I/O operations?
(A) The temporary storage of data to accommodate differences in processing speeds between I/O devices and the CPU
(B) The process of executing I/O commands
(C) The management of CPU registers
(D) The conversion of analog signals
85. How does interrupt-driven I/O differ from programmed I/O in terms of CPU involvement?
(A) Both methods involve the CPU handling I/O operations concurrently
(B) Programmed I/O requires less CPU involvement
(C) Interrupt-driven I/O allows the CPU to handle other tasks while waiting for I/O operations, whereas programmed I/O requires the CPU to wait for completion
(D) Interrupt-driven I/O increases CPU cycles for data transfer
86. What is the main disadvantage of programmed I/O?
(A) It increases the efficiency of data transfer
(B) It requires more complex hardware compared to other methods
(C) It reduces the number of interrupts generated
(D) It can be inefficient because the CPU is occupied with I/O operations, reducing overall performance
87. What does an I/O controller manage in a computer system?
(A) The execution of software programs
(B) The communication between the CPU and I/O devices
(C) The management of CPU cache
(D) The conversion of data signals
88. What is the role of an interrupt handler in an interrupt-driven I/O system?
(A) To convert digital signals to analog
(B) To handle data storage
(C) To process and manage interrupts and execute appropriate actions
(D) To execute arithmetic operations
89. In which type of I/O system does the CPU perform data transfers directly between memory and the I/O device?
(A) Memory-mapped I/O
(B) Direct Memory Access (DMA)
(C) Interrupt-driven I/O
(D) Programmed I/O
90. What is the main advantage of using a DMA controller?
(A) It simplifies the buffering process
(B) It allows for efficient data transfer without requiring constant CPU intervention
(C) It reduces the number of interrupts required
(D) It handles arithmetic calculations
91. What does “memory-mapped I/O” mean in terms of accessing I/O devices?
(A) I/O devices are accessed using separate data buses
(B) I/O devices are accessed through dedicated I/O instructions
(C) I/O devices are accessed through the same memory address space as regular memory
(D) I/O devices require manual data conversion
92. What is the impact of buffering on I/O performance?
(A) Buffering increases the number of interrupts generated
(B) Buffering decreases the overall system performance
(C) Buffering has no impact on I/O performance
(D) Buffering can improve performance by accommodating differences in processing speeds and reducing I/O wait times
93. How does an I/O bus improve the efficiency of I/O operations?
(A) By isolating I/O operations from memory access
(B) By providing a standardized pathway for data transfer between the CPU, memory, and I/O devices
(C) By directly managing I/O device interrupts
(D) By simplifying the data conversion process
94. What role does a system interrupt play in I/O operations?
(A) It converts analog signals to digital
(B) It manages the data transfer between memory and I/O devices
(C) It signals the CPU to stop its current task and handle an I/O request
(D) It executes arithmetic operations
95. Which of the following is a characteristic of Direct Memory Access (DMA) operations?
(A) DMA involves constant CPU polling of I/O devices
(B) DMA requires the CPU to manage every data transfer operation
(C) DMA increases the number of interrupts required
(D) DMA allows for high-speed data transfer with minimal CPU involvement
96. What is the main function of an I/O port?
(A) To manage the CPU’s execution of instructions
(B) To provide an interface for connecting and communicating with I/O devices
(C) To store data permanently
(D) To convert digital data to analog
97. Which type of I/O system is characterized by the CPU issuing I/O commands and directly managing data transfer operations?
(A) Interrupt-driven I/O
(B) Direct Memory Access (DMA)
(C) Programmed I/O
(D) Memory-mapped I/O
98. How does the use of interrupts benefit the handling of I/O operations?
(A) It decreases the efficiency of data transfer
(B) It requires the CPU to actively manage every I/O operation
(C) It simplifies the buffering process
(D) It allows the CPU to perform other tasks while waiting for I/O operations to complete
99. What is the purpose of an interrupt vector table in an I/O system?
(A) To manage data buffers
(B) To map interrupt requests to the corresponding interrupt service routines
(C) To execute memory operations
(D) To convert data signals
100. Which component is responsible for generating interrupts in an I/O system?
(A) The system bus
(B) The CPU
(C) Memory units
(D) I/O devices