1. The main objective of an I/O system is to:
A) Increase CPU speed
B) Provide uniform interface to I/O devices
C) Reduce memory usage
D) Eliminate interrupts
B) Provide uniform interface to I/O devices
2. Which component controls communication between CPU and I/O devices?
A) Device controller
B) Cache memory
C) Main memory
D) ALU
A) Device controller
3. Programmed I/O means:
A) CPU executes instructions while I/O happens
B) CPU waits actively for I/O completion
C) I/O works independently of CPU
D) DMA controls I/O
B) CPU waits actively for I/O completion
4. Which I/O technique allows CPU to perform other tasks during I/O?
A) Programmed I/O
B) Polling
C) Interrupt-driven I/O
D) Busy waiting
C) Interrupt-driven I/O
5. An interrupt is generated when:
A) CPU finishes execution
B) An I/O operation completes
C) Memory is full
D) Disk is idle
B) An I/O operation completes
6. Interrupt latency refers to:
A) Time to complete I/O
B) Time taken to service an interrupt
C) Time between two interrupts
D) Time CPU remains idle
B) Time taken to service an interrupt
7. Which I/O technique is best for high-speed data transfer?
A) Programmed I/O
B) Interrupt-driven I/O
C) DMA
D) Polling
C) DMA
8. DMA stands for:
A) Direct Memory Allocation
B) Direct Memory Access
C) Dynamic Memory Access
D) Data Memory Allocation
B) Direct Memory Access
9. In DMA, data transfer occurs between:
A) CPU and I/O device
B) Cache and CPU
C) Main memory and I/O device
D) Disk and disk controller only
C) Main memory and I/O device
10. Which I/O technique minimizes CPU involvement?
A) Polling
B) Programmed I/O
C) Interrupt-driven I/O
D) DMA
D) DMA
11. Buffering is used to:
A) Increase disk size
B) Handle speed mismatch between devices
C) Eliminate interrupts
D) Avoid deadlock
B) Handle speed mismatch between devices
12. Single buffering uses:
A) One buffer
B) Two buffers
C) Multiple buffers
D) No buffers
A) One buffer
13. Double buffering improves performance by:
A) Increasing CPU speed
B) Overlapping I/O and computation
C) Reducing memory usage
D) Eliminating interrupts
B) Overlapping I/O and computation
14. Caching differs from buffering because caching:
A) Is temporary storage only
B) Stores frequently accessed data
C) Is used only for I/O devices
D) Eliminates context switching
B) Stores frequently accessed data
15. Spooling stands for:
A) Simultaneous Peripheral Operation On-Line
B) Sequential Peripheral Operation On-Line
C) Simultaneous Process Operation On-Line
D) Sequential Process Operation On-Line
A) Simultaneous Peripheral Operation On-Line
16. Spooling is commonly used in:
A) Disk scheduling
B) Printer management
C) CPU scheduling
D) Memory management
B) Printer management
17. Device drivers are:
A) Hardware components
B) Application programs
C) OS modules that control devices
D) Compiler routines
C) OS modules that control devices
18. Which of the following provides device independence?
A) Device driver
B) Device controller
C) DMA controller
D) Cache memory
A) Device driver
19. Which I/O method continuously checks device status?
A) DMA
B) Interrupt-driven I/O
C) Polling
D) Spooling
C) Polling
20. Which I/O technique wastes CPU cycles?
A) DMA
B) Interrupt-driven I/O
C) Polling
D) Caching
C) Polling
21. Asynchronous I/O means:
A) CPU waits for I/O completion
B) CPU and I/O work concurrently
C) I/O is disabled
D) CPU executes only I/O instructions
B) CPU and I/O work concurrently
22. Synchronous I/O means:
A) CPU continues execution
B) CPU waits until I/O completes
C) I/O works independently
D) DMA is mandatory
B) CPU waits until I/O completes
23. Which I/O system hides device-specific details from users?
A) File system
B) Device controller
C) I/O subsystem
D) BIOS
C) I/O subsystem
24. Which of the following improves overall I/O throughput?
A) Buffering
B) Caching
C) Spooling
D) All of the above
D) All of the above
25. I/O scheduling is primarily concerned with:
A) CPU allocation
B) Order of I/O request servicing
C) Memory paging
D) Deadlock prevention
B) Order of I/O request servicing