Deck 20: Exploring the Linux Operating Systems Features and Functionality

Question 1

An advantage of the Linux operating system over proprietary systems is that ________.

A) Linux organization are required to provide free technical support
B) Linux is free to download and install
C) Linux is unlicensed
D) all of the above

Answer 1

Linux is free to download and install

Question 2

By default, Linux supports ________.

A) symmetric multiprocessing (SMP)
B) cache-only memory access (COMA)
C) programs written for operating systems including Windows and MacOS
D) all of the above

Answer 2

symmetric multiprocessing (SMP)

Question 3

Linux was originally developed ________.

A) to replace UNIX
B) as a hobby project
C) for professors to use in class to demonstrate operating system implementation issues
D) because no other open-source operating system existed

Answer 3

as a hobby project

Question 4

Stable versions of the Linux kernel are assigned an ________.

A) odd minor version number
B) odd major version number
C) even major version number
D) even minor version number

Question 5

Torvalds decided that Linux should conform to the ________ specification to enhance its interoperability with other UNIX-like systems.

A) POSIX
B) ISO
C) SUS
D) LSB

Question 6

Which of the following statements accurately describes why Linux is not installed on a significant number of personal computers?

A) Linux is harder to install than operating systems such as Windows and MacOS.
B) Microsoft's market power hampers Linux's popularity on personal computers.
C) Linux is less stable than other popular operating systems.
D) all of the above

Question 7

Linux systems include ________.

A) the kernel and user interfaces
B) user interfaces and applications
C) the kernel, user interfaces and applications
D) the kernel only

Question 8

A daemon ________.

A) remains dormant until the scheduler or another component of the kernel wakes it
B) enforces the system's security policies
C) spawns all other tasks in the system
D) none of the above

Question 9

When the development of a new stable kernel is near completion, a ________ occur(s)-only code that fixes bugs is allowed.

A) code freeze
B) feature freeze
C) distribution freeze
D) version freeze

Question 10

The GPL states that any software distributed under its license ________.

A) can be freely redistributed
B) must be delivered free of charge
C) must be accompanied by its source code
D) a and b only

Question 11

Which of the following Linux organizations is not-for-profit?

A) Debian
B) Mandrake
C) Red Hat
D) SuSE

Question 12

________ is not a shell.

A) bash
B) csh
C) esh
D) none of the above

Question 13

The three layers that compose a typical GUI on a Linux system are ________, ________ and ________.

A) the kernel, a video driver, the X Window System
B) the X Window System, a display adapter, a desktop environment
C) the X Window System, a window manager, a desktop environment
D) a desktop environment, a video driver, a display adapter

Question 14

Version 3 of the Single UNIX Specification combines several standards, including the________ and ________ standards.

A) POSIX, LSB
B) LSB, ISO
C) ISO, POSIX
D) ISO, BSD

Question 15

To bear the UNIX trademarked name, an operating system must conform to ________.

A) POSIX
B) SUS
C) LSB
D) none of the above

Question 16

Linux is a best described as a(n) ________ kernel.

A) monolithic
B) layered
C) micro
D) exo

Question 17

________ is not one of Linux's primary subsystems?

A) Process management
B) Virtual file system
C) Networking
D) Interprocess communication

Question 18

The Linux kernel initially supported the _________ platform.

A) Intel x86
B) Sun SPARC
C) Motorola 68000
D) all of the above

Question 19

The kernel's _________ organizes each significant component of the kernel into different subdirectories.

A) architecture-specific code
B) distribution
C) source tree
D) UML

Question 20

Loadable kernel modules are important because ________.

A) they impose a modular structure on the Linux kernel
B) they can reduce the kernel's memory footprint
C) they allow modifications to the kernel without recompiling the kernel
D) b and c only

Question 21

_________ is the kernel subsystem that manages modules without user interaction

A) lkm
B) kloadmod
C) kmod
D) kautoload

Question 22

In Linux systems, a task represents a ________.

A) process
B) thread
C) job
D) a and b only

Question 23

A task transitions to the ________ state when it is dispatched to a processor.

A) running
B) ready
C) executable
D) dispatch

Question 24

The priority array that contains tasks in the active state is called the ________.

A) current list
B) runnable list
C) active list
D) ready list

Question 25

A task's effective priority is calculated when ________.

A) a task sleeps
B) a task sleeps or consumes its time slice
C) a task consumes its time slice or is awakened by another thread
D) a task sleeps, consumes its time slice or is awakened by another thread.

Question 26

Real-time tasks always execute ________.

A) in a FIFO ordering
B) in a FIFO ordering and with lower priority (higher nice) than normal tasks
C) in a round-robin ordering and with higher priority (lower nice) than normal tasks
D) with higher priority (lower nice) than normal tasks

Question 27

The memory manager supports ________ to allow it to scale from desktop computers and workstations to servers and supercomputers

A) 32-bit addresses
B) 64-bit addresses
C) nonuniform memory access architecture
D) all of the above

Question 28

The virtual memory system supports up to ________ levels of page tables to locate the mappings between virtual pages and page frames.

A) 2
B) 3
C) 4
D) none of the above. The kernel supports an arbitrary number of levels.

Question 29

Although a process's virtual address space is composed of individual pages, the kernel uses a higher-level mechanism, called ________, to organize the virtual memory a process is using.

A) page global directories
B) segments
C) virtual memory areas
D) none of the above

Question 30

The ________ zone includes the main memory locations from 0-16MB.

A) DMA memory
B) normal memory
C) high memory
D) none of the above

Question 31

The kernel allocates page frames to processes using the _________.

A) page cache
B) slab allocator
C) zone allocator
D) slab cache

Question 32

A ________ is a region of memory that the kernel guarantees will be available to a kernel thread or device driver regardless of how much memory is currently occupied.

A) page cache
B) slab cache
C) DMA memory
D) memory pool

Question 33

The ________ is designed to reduce the time spent performing disk I/O operations.

A) slab cache
B) page cache
C) slab allocator
D) zone allocator

Question 34

If a page corresponds to a process's data or procedure page, kswapd writes it to a region of data in secondary storage called the ________.

A) system swap file
B) swap cache
C) slab file
D) backing store

Question 35

A page chosen for replacement cannot be immediately swapped if ________.

A) the page is shared and is read-only
B) the page is shared or has been modified
C) the page is shared, has been modified or is locked
D) the page is shared or the system swap file is full

Question 36

By abstracting the concept of a file, the kernel can access _________ via the VFS.

A) block I/O devices
B) network devices
C) interprocess communication primitives
D) Both a and b

Question 37

The VFS ________.

A) schedules disk I/O
B) implements functions such as read and write
C) interprets data from superblocks, files, inodes and directory entries
D) all of the above

Question 38

Linux uses files to represent ________.

A) named sets of data
B) hardware devices
C) shared memory regions
D) all of the above

Question 39

To improve performance for file and directory access, the virtual file system maintains the _________ and _________ caches.

A) directory entry, inode
B) swap, slab
C) swap, directory entry
D) slab, inode

Question 40

When resolving a pathname to its corresponding data, the VFS first ________, then _________ and finally _________.

A) calls the file system's lookup function, checks the inode cache, checks the dentry cache
B) checks the dentry cache, checks the inode cache, calls the file system's lookup function
C) checks the dentry cache, calls the file system's lookup function, returns a file not found error.
D) calls the file system's lookup function, checks the dentry cache, checks the inode cache

Question 41

If an ext2 file system uses 2KB blocks, a file smaller than ________ can be located directly from its inode.

A) 16KB
B) 20KB
C) 24KB
D) 48KB

Question 42

By default, ________ percent of the blocks are reserved exclusively for users with root privileges when the disk is formatted.

A) twenty-five
B) ten
C) five
D) one

Question 43

Procfs is a file system ________.

A) can be accessed only by a user with root privileges
B) that exists only in main memory
C) contains VFS directory entries
D) that is read-only

Question 44

Procfs was created to provide real-time information about the status of ________ in a system.

A) network devices
B) processes
C) mounted file systems
D) all of the above

Question 45

________ has/have written most of the drivers that operate devices commonly found in Linux systems.

A) Linus Torvalds
B) Independent Linux developers
C) Device manufacturers
D) both b and c

Question 46

Which of the following statements is false?

A) Most devices in a system are represented by device special files.
B) Devices that are controlled by the same major identification number are controlled by the same driver.
C) Device classes include character, block and network.
D) Device special files are accessed via the virtual file system.

Question 47

A ________ transmits data as a stream of bytes.

A) block device
B) network device
C) character device
D) none of the above

Question 48

The ________ structure maintains the operations supported by a device driver.

A) device_struct
B) file_operations
C) chrdevs
D) bio

Question 49

The deadline scheduler ________.

A) implements separate FIFO queues for read and write requests.
B) ensures that read requests are serviced before their deadlines
C) ensures that write requests are serviced before their deadlines
D) all of the above

Question 50

The anticipatory and deadline schedulers are different in that ________.

A) the anticipatory scheduler prevents read request starvation, whereas the deadline scheduler is more appropriate for real-time systems
B) the anticipatory scheduler prevents read request starvation by introducing a 6ms pause after each read request
C) the deadline scheduler is more appropriate when write requests and synchronous read requests occur concurrently
D) both a and b

Question 51

When processes submit network data to the socket interface, they specify ________.

A) the network address of the destination
B) a reference to a network device driver
C) the MAC address of the network interface card
D) none of the above

Question 52

________ determines the order in which packets are processed.

A) The kernel
B) Each network interface card
C) Each device driver
D) A process that submits packets

Question 53

The unified device model defines data structures to represent ________.

A) devices
B) device drivers
C) buses
D) all of the above

Question 54

The unified device model ________.

A) enables the kernel to use device classes to determine the bus to which a device is attached
B) organizes a systems' devices, device classes, device drivers and buses hierarchically
C) was required to implement Plug and Play
D) Both a and c.

Question 55

When the kernel receives an interrupt from a hardware device, it passes control to ________.

A) the bottom half of the driver's interrupt handler
B) the top half of the driver's interrupt handler
C) a softirq
D) tasklet

Question 56

________ are reentrant interrupt handlers.

A) Softirqs
B) Tasklets
C) top half interrupt handlers
D) none of the above

Question 57

To protect data shared between user contexts and software interrupt handlers, the kernel uses ________ spin locks.

A) bottom-half
B) top-half
C) reader/writer
D) seqlock

Question 58

________ allow multiple kernel controls paths to hold a read lock, but permit only one kernel control path to hold a write lock with no concurrent readers.

A) Reader spin locks
B) Writer spin locks
C) Kernel semaphores
D) None of the above

Question 59

To prevent indefinite postponement and provide writers with fast access to critical sections, kernel control paths use ________.

A) kernel semaphores
B) writer locks
C) reader locks
D) seqlocks

Question 60

Because the value of the seqlock's sequence counter is initialized to zero, a(n) ________ is being executed when that value is odd.

A) read
B) write
C) interrupt handler
D) softirq

Question 61

When a critical section must be protected for a long time, ________ are a better choice for implementing mutual exclusion.

A) reader/writer locks
B) seqlocks
C) kernel semaphores
D) kernel monitors

Question 62

________ were one of the first interprocess communication mechanisms available in UNIX systems.

A) signals
B) pipes
C) sockets
D) message queues

Question 63

A process or thread can handle a signal by ________.

A) ignoring the signal
B) catching the signal
C) executing the default action that the kernel defines for that signal
D) all of the above

Question 64

One limitation of pipes is that they support communication only between processes that share a ________.

A) region of virtual memory
B) file descriptor
C) parent
D) pipe buffer

Question 65

Sockets ________.

A) are used for unidirectional communication between processes on separate computers
B) are used for bidirectional communication between processes on the same computer and processes on separate computers
C) are represented internally as files, and can be accessed via read and write calls.
D) both b and c

Question 66

Related processes can search for a ________ in an array of ________.

A) message, message queue descriptors
B) message queue descriptor, message queue identifiers
C) message queue identifier, message queue descriptors
D) message queue descriptors, messages

Question 67

________ implements shared memory for the ________ specification.

A) Psxfs, POSIX
B) Tmpfs, POSIX and System V
C) shmfs, System V
D) both a and c

Question 68

________ are synchronization mechanisms employed throughout the kernel to protect access to critical sections.

A) Kernel semaphores
B) System V semaphores
C) POSIX semaphores
D) none of the above

Question 69

Because processes often need to protect a number of related resources, the kernel stores semaphores in ________.

A) semaphore lists
B) semaphore arrays
C) semaphore queues
D) none of the above

Question 70

The transport layer packet handler supports the ________.

A) Transmission Control Protocol (TCP)
B) User Datagram Protocol (UDP)
C) Control Message Protocol (ICMP)
D) all of the above

Question 71

The first netfilter hook packets encounter is ________.

A) NF_IP_LOCAL_IN
B) NF_IP_LOCAL_OUT
C) NF_IP_PRE_ROUTING
D) NF_IP_FORWARD

Question 72

The thrust of Linux scalability development is to ________.

A) enable the Linux kernel to scale to high-end servers
B) improve performance on desktop systems
C) enable the Linux kernel to perform well on embedded systems.
D) both a and c

Question 73

The earliest implementation of multiprocessor synchronization for the Linux kernel used the ________ to lock the kernel on all other processors.

A) big kernel lock
B) global kernel lock
C) global system lock
D) None of the above.

Question 74

Locking the entire kernel is usually not required, because ________.

A) processes on other processors are almost always executing in user mode.
B) kernel data structures are mostly read-only.
C) multiple processes can execute concurrently in kernel mode provided they do not modify the same data structures.
D) all of the above

Question 75

NUMA architectures divide a system into nodes, each of which provides high-performance interconnections between ________.

A) processors
B) memory
C) I/O devices
D) all of the above

Question 76

Most NUMA systems partition a single ________ into regions corresponding to each node.

A) virtual memory address space
B) physical memory address space
C) disk
D) all of the above

Question 77

In version 2.6, developers ________, improving real-time performance.

A) added support for deadline process scheduling
B) made the kernel preemptible
C) increased the size of jiffies
D) all of the above

Question 78

Embedded-device developers modify the kernel's ________.

A) scheduler to support additional priority levels, deadlines and lower scheduling latency
B) virtual file system to support low-capacity storage devices
C) network layer to support wireless networking
D) all of the above

Question 79

Passwords can be hashed using the ________ algorithm.

A) 3DES
B) DES
C) MD4
D) all of the above

Question 80

Linux uses ________ to support authentication via interfaces including smart cards, Kerberos and voice authorization systems.

A) Linux security modules (LSMs)
B) mandatory access control (MAC)
C) pluggable authentication modules (PAMs)
D) SELinux