CMPEN441 RedHat Quizes
Operating System Definition
OS is a resource allocator ◦ Manages all resources ◦ Decides between conflicting requests for efficient and fair resource use OS is a control program ◦ Controls execution of programs to prevent errors and improper use of the computer
what does fg do
brings a task back from the background
Caching
copying information into faster storage system; main memory can be viewed as acache for secondary storage
Solid-state disks
faster than hard disks, nonvolatile ◦ Various technologies ◦ Becoming more popular9
how is everything stored in linux
files in tree format
ssh
secure shell can access remotely from a server
System BUS
: Provides for communication among processors, main memory, and I/O modulesSupporting components (e.g. power supply, bus, fans, case)
Hard disks
rigid metal or glass platters covered with magnetic recording material ◦ Disk surface is logically divided into tracks, which are subdivided into sectors ◦ The disk controller determines the logical interaction between the device and the computer
Which item represents a number that identifies the group at the most fundamental level? A Primary group B UID C GID D Groupid
C GID
Which pattern matches only file names that begin with an uppercase letter? A ^?* B ^* C [upper]* D [[:upper:]]* E [[CAP]]*
D [[:upper:]]*
Which directory contains files to boot the system? A /boot B /home/root C /bootable D /etc
A /boot
Which directory contains persistent, system-specific configuration data? A /etc B /root C /run D /usr
A /etc
Which output redirection operator sends output to a file and sends errors to a different file? A > file 2> file2 B > file 1> file2 C > file &2> file2 D | tee file
A > file 2> file2
Which pattern matches only file names with at least three characters? A ???* B ??? C \3* D +++* E ...*
A ???*
Which term describes the part of the command line that specifies the target that the command should operate on? A Argument B Command C Option D Prompt
A Argument
Which item or file represents the location of the user's personal files? A Home directory B Login shell C /etc/passwd D /etc/group
A Home directory
Which term describes the hardware display and keyboard to interact with a system? A Physical Console B Virtual Console C Shell D Terminal
A Physical Console
Which pattern matches only file names that begin with "b"? A b* B *b C *b* D [!b]*
A b*
Which command returns to your current home directory, assuming that the current working directory is /tmp and your home directory is /home/user? A cd B cd .. C cd . D cd * E cd /home
A cd
Which Bash command is used to display the file type? A file B less C cat D history E view
A file
Which command displays the absolute path name of the current location? A cd B pwd C ls ~ D ls -d
B pwd
The set of steps that the Kernel takes to switch from one task to another in a CPU is Called
Context Switch
operating system
Managing all these components requires a layer of software
Interrupts
Mechanism by which other modules may interrupt the normal sequencing of theprocessor.
what is a system call
calls the OS context switch
!!
reruns the last command
Time multiplexing:
sharing time of use of processor, I/O, etc.
su
switch user
command to check how long a system has been running
uptime
> vs >>
> overrides content in file >> appends to the new location
Resources Managed by OS
CPU Memory Storage I/O devices
What is the fourth field of the /etc/passwd file? A Home directory B UID C Login shell D Primary group
D Primary group
3. Which pattern matches only file names where the first character is not "b"? A b* B *b C *b* D [!b]*
D [!b]*
Classes of Interrupts
Program Timer I/O Hardware failure
Space multiplexing:
sharing space on memory, disk
what is SIGINT
when you press CNTRL c it kills the process
Which Bash shortcut or command separates commands on the same line? A Pressing Tab B history C ; D !string E Pressing Esc+.
C ;
Uniprogramming
The processor spends a certain amount of time executing, until itreaches an I/O instruction; it must then wait until that I/Oinstruction concludes before proceeding
2 Types of multiplexing
Time multiplexing: Space multiplexing:
An operating system is interrupt driven T/F
True
sudo
switches the user to the root user and executes from there
what is considered a zombie program
when the child fishes executing but the parent is still waiting
what is a PCB and what does it stand for
-Process control block -context of a process
things stored in a stack
-local variables -function parameters -return addresses
Which pattern matches only file names that contain a number? A *#* B *[[:digit:]]* C *[digit]* D [0-9]
B *[[:digit:]]*
Which pattern matches only file names that end with "b"? A b* B *b C *b* D [!b]*
B *b
Which directory is the top of the system's file-system hierarchy? A /etc B / C /home/root D /root
B /
Which item or file represents the location of the local user account information? A Home directory B /etc/passwd C /etc/UID D /etc/group
B /etc/passwd
Which item represents a number that identifies the user at the most fundamental level? A Primary user B UID C GID D Username
B UID
Which term describes one of multiple logical consoles that can each support an independent login session? A Physical Console B Virtual Console C Shell D Terminal
B Virtual Console
Which command changes the working directory to the parent of the current location? A cd ~ B cd .. C cd ../.. D cd -u1
B cd ..
Multiprogramming
There must be enough memory to hold the OS (resident monitor) and one user programWhen one job needs to wait for I/O, the processor can switch to the other job, which is likelynot waiting for I/O Also known as multitasking Memory is expanded to hold three, four, or more programs and switch among all ofthem7
how to add a new user to the terminal
add userer
Asymmetric Multiprocessing
each processor is assigned a specie task.
Symmetric Multiprocessing
each processor performs all tasks
Secondary storage
extension of main memory that provides large nonvolatile storage capacity
shell scrips must be compiled and executed
false
can a process go from blocked to running
no
can a signal create a new process
no
Main memory
only large storage media that the CPU can access directly ◦ Random access ◦ Typically volatile
& in command Linux line
sends a tasks to the background
Which command returns you to the working directory before the current working directory? A cd - B cd -p C cd ~ D cd ..
A cd -
Storage Device Hierarchy
1 registers 2 cache 3 main memory 4 solid state drive 5 hard disk 6 optical disk 7 magnetic tapes
Which Bash shortcut or command re-executes a specific command in the history list? A Pressing Tab B !number C !string D history E Pressing Esc+.
B !number
Which output redirection operator discards all messages that are normally sent to the terminal? A > file 2> file2 B &> /dev/null C &> /dev/null 2> file D &> file
B &> /dev/null
Which directory contains user home directories? A / B /home C /root D /user
B /home
Which term describes the name of a program to run? A Argument B Command C Option D Prompt
B Command
Which command creates an empty file called helloworld.py in the user home directory, assuming that your current directory is /home? A touch ./helloworld.py B touch ~/helloworld.py C touch helloworld.py D touch ../helloworld.py
B touch ~/helloworld.py
Which pattern matches all file names that contain a "b"? A b* B *b C *b* D [!b]*
C *b*
Which directory contains system files to access hardware? A /etc B /run C /dev D /usr
C /dev
Which directory contains non-persistent process runtime data? A /tmp B /etc C /run D /var
C /run
Which directory contains installed software programs and libraries? A /etc B /lib C /usr D /var
C /usr
Which directory contains regular commands and utilities? A /commands B /run C /usr/bin D /usr/sbin
C /usr/bin
Which output redirection operator displays output to a terminal and discards all error messages? A &> file B 2> &> file C 2> /dev/null D 1> /dev/null
C 2> /dev/null
Which output redirection operator sends output and errors to the same file and preserves the file content if it exists? A > file 2> file2 B &> file C >> file 2>&1 D >> file 1>&1
C >> file 2>&1
Which item represents the program that provides the user's command-line prompt? A Primary shell B Home directory C Login shell D Command name
C Login shell
Which term describes the part of the command line that adjusts the behavior of a command? A Argument B Command C Option D Prompt
C Option
Which term describes the interpreter that executes commands that are typed as strings? A Command B Console C Shell D Terminal
C Shell
Which command changes the working directory up two levels from the current location? A cd ~/.. B cd ../ .. C cd ../.. D cd ~/
C cd ../..
Which command changes the working directory to /tmp if the current working directory is /home/student? A cd tmp B cd .. C cd ../../tmp D cd ~tmp
C cd ../../tmp
Which Bash command is used to change a user's password? A password B pass C passwd D usermod E userpassword
C passwd
Which Bash command displays the last five lines of the /var/log/messages file? A head -n 10 /var/log/messages B tail 10 /var/log/messages C tail -n 5 /var/log/messages D tail -l 10 /var/log/messages E less /var/log/messages
C tail -n 5 /var/log/messages
Which output redirection operator sends output to both the screen and a file at the same time? A &> /dev/null B > file 2> file2 C | tee file D | < file
C | tee file
Which output redirection operator sends both output and errors to a file, and creates it or overwrites its contents? A | tee file B 2 &> file C 1 &> file D &> file
D &> file
Which item or file represents the location of the local group information? A Home directory B /etc/passwd C /etc/GID D /etc/group
D /etc/group
Which directory is the administrative superuser's home directory? A /etc B / C /home/root D /root
D /root
Which output redirection operator saves output to a file and discards all error messages? A &> file B | tee file 2> /dev/null C > file 1> /dev/null D > file 2> /dev/null
D > file 2> /dev/null
Which Bash shortcut or command copies the last argument of previous commands? A Pressing Ctrl+K B Pressing Ctrl+A C !number D Pressing Esc+.
D Pressing Esc+.
Which Bash shortcut or command is used for completing commands, file names, and options? A ; B !number C history D Pressing Tab E Pressing Esc+.
D Pressing Tab
Which term describes the visual cue that indicates that an interactive shell is waiting for the user to type a command? A Argument B Command C Option D Prompt
D Prompt
Which term describes an interface that provides a display for output and a keyboard for input to a shell session? A Console B Virtual Console C Shell D Terminal
D Terminal
Which Bash shortcut or command displays the list of previously executed commands? A Pressing Tab B !string C !number D history E Pressing Esc+.
D history
Which command lists files in the current location, with a long format, and including hidden files? A llong ~ B ls -a C ls -l D ls -al
D ls -al
Which Bash shortcut or command jumps to the beginning of the command line? A !number B !string C Pressing Ctrl+LeftArrow D Pressing Ctrl+K E Pressing Ctrl+A
E Pressing Ctrl+A
PSW
Program Status Word Contains a list of bits Each bit represents a status or an event within the computer system. These Bits are called "Flag Bits"
System Bus
Provides for communication amongprocessors, main memory, and I/Omodules4
When you shut down a computer what loses its data
RAM
kernel
The core functionality of an operatingSystem "The one program running at all times on the computer"
Device Driver
device controller to manage I/O ◦ Provides uniform interface between controller and kernel10