Operating System MCQs with Answers
Practice important Operating System MCQs with answers and explanations.
Multiple Choice Questions
Q1021: The valid-invalid bit in a page table entry is used to indicate:
- A: Whether the page is in memory
- B: Whether the page is locked
- C: Whether the page has been accessed recently
- D: Whether the page is valid for execution
View Answer
A
Q1022: The primary benefit of virtual memory is that it allows:
- A: Efficient use of available physical memory
- B: Faster CPU performance
- C: Direct access to physical memory
- D: None of the above
View Answer
A
Q1023: In demand paging, when a page fault occurs, the operating system must do which of the following?
- A: Swap the entire process into memory
- B: Read the page from disk and load it into memory
- C: Terminate the process
- D: Allocate more CPU cycles
View Answer
B
Q1024: What is the primary goal of page replacement algorithms?
- A: Minimize disk space
- B: Minimize number of page faults
- C: Increase memory usage
- D: Minimize process execution time
View Answer
B
Q1025: What is the formula for calculating Effective Access Time (EAT)?
- A: 100 * (1-p) + (105 + 2 * 104 + 0.5 * 107 + 0.5 * 2 * 107) * p
- B: 100 * (1-p) + (105 + 2 * 104 + 0.5 * 107 + 0.5 * 2 * 107) * p
- C: 100 * p + (105 + 2 * 104 + 0.5 * 107 + 0.5 * 2 * 107) * p
- D: None of the above
View Answer
B
Q1026: What is the page fault rate for a good performance?
- A: Above 50%
- B: Below 1%
- C: Above 5%
- D: None of the above
View Answer
B
Q1027: What system call is used to create a child process as a duplicate of its parent?
- A: fork()
- B: exec()
- C: clone()
- D: vfork()
View Answer
A
Q1028: Which memory management technique is used to minimize the number of new pages allocated to child processes?
- A: Copy on Write
- B: Demand Paging
- C: Memory Mapped Files
- D: Page Replacement
View Answer
A
Q1029: What is the main difference between fork() and vfork()?
- A: vfork() creates a new process with its own address space
- B: fork() uses copy-on-write to create a child process
- C: vfork() creates a child process using the parent's address space
- D: fork() operates slower than vfork()
View Answer
C
Q1030: In which system call are shared pages marked as read-only after the fork() system call?
- A: mmap()
- B: fork()
- C: vfork()
- D: clone()
View Answer
B