Quiz: Linux Basics (Solution)

User Space, Kernel Space

  • Kernel/user space: which of the following statements are true?

    Statement

    True

    False

    In kernel space there exists the concept of a process

    n

    In user space there exists the concept of a process

    y

    Interrupts are generally serviced in user space

    n

    Interrupts are generally serviced in kernel space

    y

    Scheduling of processes is done by the kernel

    y

    Address spaces are implemented in user space

    n

  • How do programs communicate with the kernel? (One answer)

    Statement

    True

    False

    System calls

    y

    Message queues

    n

    IO ports

    n

    Reverse interrupts

    n

  • File abstraction: which concepts are represented by file decriptors?

    Statement

    True

    False

    Files

    y

    Network sockets

    y

    Timers

    y

    Serial/UART devices

    y

    Memory

    n

    The process stack

    n

  • The term “blocking” describes which behavior? (One answer)

    Statement

    True

    False

    A process can block another for communication purposes

    n

    A process consumes no CPU time while it waits for an event to happen

    y

    The kernel blocks access to network resources to enhance system security

    n

Processes, Scheduling, and Virtual Memory

  • Scheduling: which of the following statements are true?

    Statement

    True

    False

    A timeslice is the amount of time that a process can run until it is suspended in favor of other processes

    y

    Fair scheduling ensures that network resources are evenly shared

    n

    On a single-CPU machine, no process may enter an infinite loop - or else, the entire machine will come to a halt

    n

    Fair scheduling ensures that every process gets its fair share of CPU resources

    y

    The scheduler gives processes the illusion that each of them owns the CPU

    y

    A context switch happens when one process enters a blocking system call

    y

  • Virtual Memory: which of the following statements are true?

    Statement

    True

    False

    A process can own all memory in the system

    n

    The kernel is the owner of all memory in the system

    y

    All processes share a single address space

    n

    Each process in the system has its own address space

    y

    An address space is three-dimensional

    n

  • Processes: which of the following statements are true?

    Statement

    True

    False

    A process is identified by its process ID

    y

    A process is identified by its pthread context number

    n

    Processes are arranged in a process hierarchy, starting at process 1

    y

    A process may have multiple parents

    n

    Every process has a parent process

    n

    Every process except process 1 has a parent process

    y