Kernel Programming - Solaris MCQ Questions Answers

1. Which of the following structures keeps track of the in memory user data pages associated with a file?

2. Which of the following data is penalized (swapped) first if the OS detects low memory conditions?

3. Where are the 64 bit kernel modules located?

4. What is the maximum number of registers available to a function at any time?

5. What are the names of the symbol file and the memory image files following a kernel dump?

6. Which of the following is the correct locking hierarchy for filesystems which implement the mmap interface?

7. Which of the following registers contains the thread pointer of the thread that is currently being run?

8. Why should floating point operations be avoided in drivers?

9. What does the cv_wait_sig interface do?

10. Is it possible to take a core dump of a live system?

11. Which of the following interfaces must be implemented by every loadable driver?

12. Which of the following interfaces is equivalent to acquiring a lock?

13. Following a panic and a core dump, what is done to recreate the core files for debugging?

14. Which of the following sparc instructions causes a register window context to be created?

15.

Where is the following memory allocation type typically employed?

memp = kmem_alloc(size, KM_NOSLEEP);

16. Which of the following does the OS use for caching user data?

17. Which of the following CV interfaces can be used to wakeup exactly one waiter?

18. Which of the following locks is used to serialize reads and writes on a vnode?

19. Which of the following kadb macros is useful in determining the panic address?

20. What does the VFS_ROOT interface do?

21. Is the memory allocated by kmem_alloc paged?

22. Which of the following buffer structure fields specifies the direction of IO transfer, the transfer size and the virtual address of the data?

23. Which of the following interfaces to a block device driver does the filesystem use?

24. Which of the following types of information is stored within the buffer cache?

25. Which of the following is true if an interrupt thread needs to block on a resource?

26. Which of the following sequences involving a CV is correct if a thread wants to wait for an event?

27. Which of the following abstractions enables a multi-threaded application to take advantage of the available parallelism?

28. What sequence of key strokes is required to trap into the kadb in a live session?

29. In which of the following contexts do callouts run?

30. Which of the following caches doesnot change its size dynamically on older solaris systems?

31. On a sparc system, which of the register set of a calling function is passed on as input registers to the called function?

32. What is the correct way of initializing a mutex on solaris?

33. Can the solaris semaphores be used in the interrupt context?

34. What is the kernel interface to initialize a reader writer lock?

35. What is the compiler option to generate a 64 bit binary loadable on a sparc machine?

36. What are the commands to load and unload the kernel module 'mymod'?

37. Which of the following operations results in the page cache being populated?

38. What happens if a driver running on a sparc processor tries to access a 32 bit quantity which is aligned on a 16 bit boundary?

39. What is the command to boot into the kernel debugger (kadb) from an 'ok' prompt?

40. Which of the following debuggers allow extensive customization and supports user written pluggable debugging modules?

41. Which of the following kernel defined data types is involved in the interface calls to manipulate CVs?

42. The OS can unload a module automatically if needed.

43. Is the solaris kernel fully preemtible?

44. Which of the following kadb/adb macros can be used to examine the stack traces of all the kernel threads?

45. What does the OS do when it detects a page fault on a valid address?

46. Which of the following kernel subsystems employs a semaphore for synchronization?

47. Is the thread allowed to perform any kind of blocking operation while holding a mutex?

48. Is the glock necessary if a filesystem does not implement the mmap interface?

49. Which of the following mechanisms enables solaris to support real time applications?

50. If there is contention between readers and writers on an rw lock, which of them are given preference over the other?

51. Which of the following kadb/adb commands prints the contents of the register set at a particular stack depth?

52. The condition variable synchronization primitives need which of the following primitives to be employed by the client code to function correctly?

53. Which of the following interfaces does the OS call to translate path names to vnodes?

54. Which of the following information must be tracked explicitly by a driver that allocates memory via kmem_alloc?

55. Which of the following is true of the memory allocated by kmem_alloc?

56.

What does the following kernel interface do?

rw_lock_held(lock pointer);

57. Which of the following firmware commands causes a kernel core file to be dumped to the dump device?

58. How many times can a semaphore be acquired without blocking?

59. Which of the following interfaces is the preferred way for drivers to log messages?

60. The memory allocated by kmem_alloc is private to the kernel thread that allocated it.

61. Which of the following kernel interfaces can be used by a driver interface like open to identify the specific device instance involved in the operation?

62. Which of the following sparc instructions is employed before returning from a function to restore the original context?

63. Which of the following commands can be used to examine the panic stack trace?

64. Which of the following has the lowest scheduling latency?

65. What is the outcome if an interrupt handler needs to block on a resource?

66. In which of the following driver interfaces should device instance specific resources be handled?

67. Can the mutex be locked by one kernel thread and unlocked by another kernel thread?

68. Which of the following sparc instructions forms the basis of all other locking strategies?

69. Which of the following sets does a breakpoint at the start of the kernel function ufs_read?

70. Solaris rw locks are recursive locks. A thread that already holds a lock in the read mode can acquire the lock in the read mode again.

71. Which of the following adb/kadb commands can be used to determine the function which caused the panic?

72. Which of the following abstractions is the fundamental schedulable entity on a solaris machine?

73. Which of the following interfaces can be used by a driver interface routine to copy data from and to the user address space?

74. Which of the following structures describes the user initiated IOs?

75. Which of the following structures keeps track of the positional offset within the file where the next IO is to be performed?

76.

On a solaris system with no special kmem_flag settings,

what happens when a thread running buggy code frees a buffer twice.

77. Which of the following commands can be used to examine and delete kernel breakpoints?

78.

What do the following mdb commands do?

::allocdby

::freedby

79.

Which of the following calls fits in at 'statement xxx'

to produce correct results in the code snippet below?

mutex_enter(mutex pointer);

while (condition is false) {

      cv_wait(cv pointer, mutex pointer);

}

statement xxx;

mutex_exit(mutex pointer);

80. What does the vfs_vnodecovered field of a vfs structure indicate?

81. Which of the following sequences correctly builds the loadable module 'mymod'?

82. What is the significance of setting the kernel global variable 'kmem_flags' to '0xf'?

83. In which of the following contexts does the solaris kernel handle interrupts?

84. Which of the following is pageable?

85. Which of the following components is responsible for speeding up file paths to inode lookups?

86. Which of the following interfaces can be used to avert a thundering herd of waiters?

87. Which of the following interfaces needs to be implemented for a filesystem to support swap files?

88. The OS guarantees that a thread blocked on a cv via a cv_wait call does not wakeup prematurely and hence does not need to re-check for the reason for blocking.

89. Which of the following interfaces is used by the driver to signal the completion of an IO initiated by a strategy call?

90. Which of the following commands prints out the kernel device tree?

91. What does the v_vfsmountedhere field of a vnode indicate?

92. What does the VOP_INACTIVE interface do?

93. Which of the following interfaces are invoked by the OS to flush all data belonging to a filesystem to a disk?

94. What are the basic mutex operations supported by the solaris operating system?

95. How many LWPs must a process have to maximize its parallelism?

96. Which of the following cache entries need to be purged/invalidated if a file is deleted?