Top Linux Sysfs Interview Questions & Answers:

1. What is sysfs?
a) it is a virtual filesystem
b) users use it to get the information about the running kernel
c) it is used for exporting kernel objects.
d) all of the mentioned

d) all of the mentioned

2. sysfs is based on:
a) rootfs
b) ramfs
c) initramfs
d) none of the mentioned

b) ramfs

3. Attributes can be exported for objects in the form of _______ in the file system.
a) regular files
b) directories
c) symbolic links
d) none of the mentioned

a) regular files

4. Sysfs is initialised in ______ file via sysfs_init function.
a) fs/sysfs/mount.c
b) sysfs/mount.c
c) fs/mount.c
c) none of the mentioned

a) fs/sysfs/mount.c

5. Kernel objects are exported as _____ via sysfs.
a) regular files
b) symbolic links
c) directories
d) none of the mentioned

c) directories

6. Sysfs internally stores the pointer to the ____ that implements the directory in the file system.
a) kobjects
b) kstructures
c) kinodes
d) none of the mentioned

a) kobjects

7. In sysfs every subsystem has:
a) a shared attribute structure
b) its own attribute structure
c) both (a) and (b)
d) none of the mentioned

b) its own attribute structure

8. Which one of the following is a notification to user space from the kernel that something has changed in the system's configuration?
a) hotplug event
b) module event
c) attach event
d) none of the mentioned

a) hotplug event

9. In the device driver model the device_driver object contains the:
a) name of the device driver
b) embedded kobjects
c) method for probing a device
d) all of the mentioned

d) all of the mentioned

10. A ____ is a higher level view of a device that abstracts out low level implementation details/
a) inode
b) class
b) major number
d) minor number

b) class

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11. When a device is removed from the system:
a) files and directories of that device in the sysfs are removed automatically
b) all the files of sysfs are preserved until the system turn offs
c) it does not create any change in the sysfs
d) none of the mentioned

a) files and directories of that device in the sysfs are removed automatically

12. Relationship between components of device driver models are expressed in the sysfs as:
a) a directory
b) a regular file
c) symbolic links between files and directories
d) none of the mentioned

c) symbolic links between files and directories

13. What is the main role of the regular files in the sysfs?
a) regular files represent the attributes of devices and drivers
b) regular files represent the kernel objects
c) regular files represent the kernel sets
d) none of the mentioned

a) regular files represent the attributes of devices and drivers

14. The core data structure of device driver model is:
a) kobject
b) kfile
c) kmodule
d) none of the mentioned

a) kobject

15. The kset contains:
a) pointer to subsystem descriptor
b) pointer to the kobject type descriptor of the kset
c) head of the kobjects included in the kset
d) all of the mentioned

d) all of the mentioned

16. Which one of the following is a read-write semaphore in linux that protects all ksets and kobjects included in the filesystem?
a) rwsem
b) rwsemaphore
c) rws
d) none of the mentioned

a) rwsem

17. Each device in the device driver model is represented by a _____ object.
a) driver
b) device
c) node
d) none of the mentioned

b) device

18. Each driver in the device driver model is described by a ______ object.
a) dev_d
b) device_d
c) dev_driver
d) device_driver

d) device_driver

19. The channel between the processor and devices is called?
a) bus
b) driver
c) class
d) none of the mentioned

a) bus

20. In which directory every kernel module of the system is represented?
a) /sys/kernel
b) /sys/module
c) /sys/kernel/module
d) none of the mentioned

c) /sys/kernel/module

21. In sysfs the device drivers of same _____ are expected to provide same functionalities to the user mode application.
a) class
b) kobjects
c) ksets
d) none of the mentioned

a) class

22. The directories in the /sys directory represents:
a) the device files
b) major subsystems that are registered with sysfs
c) details of buses only
d) none of the mentioned

b) major subsystems that are registered with sysfs

23. Sysfs does not contains:
a) regular files
b) symbolic links
c) directories
d) none of the mentioned

d) none of the mentioned

24. Sysfs represents the:
a) kernel objects
b) libraries
c) API
d) none of the mentioned

a) kernel objects

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25. Libsysfs is a:
a) user space library
b) kernel space library
c) not a library
d) none of the mentioned

a) user space library

26. In linux sysfs is always mounted at:
a) /sys
b) /proc/sys
c) /proc/mounts
d) none of the mentioned

a) /sys

27. Which one of the following is not true?
a) any file of the sysfs can not be edited
b) some files of the sysfs are writable for configuration of devices
c) both (a) and (b)
d) none of the mentioned

b) some files of the sysfs are writable for configuration of devices

28. The files of sysfs contains the information about:
a) devices and drivers
b) memory mapping
c) ports
d) none of the mentioned

a) devices and drivers

29. Sysfs can be considered as the reflection of the:
a) kernel's device model
b) user's device model
c) network's device model
d) none of the mentioned

a) kernel's device model

30. Sysfs was originally called:
a) device driver filesystem
b) kernel interface filesystem
c) kernel filesystem
d) none of the mentioned

a) device driver filesystem

31. Sysfs attribute should export ____ value per file.
a) one
b) two
c) three
d) four

a) one

32. Which one of the following function is used to create a new attribute?
a) sysfs_create_file()
b) sysfs_attribute
c) both (a) and (b)
d) none of the mentioned

a) sysfs_create_file()

33. Which one of the following function is used to add the kobject to sysfs?
a) kobject_add()
b) kobject_register()
c) kobject_init()
d) all of the mentioned

d) all of the mentioned

34. Which one of the following is a element of a kset data structure?
a) pointer to the subsystem descriptor
b) pointer to the kobject type descriptor of the kset
c) both (a) and (b)
d) none of the mentioned

c) both (a) and (b)

35. The kobjects can be organized in a hierarchical tree by means of:
a) ksets
b) kref
c) ktype
d) none of the mentioned

a) ksets