Kickoff

Linux crash course

What is Linux

• Free and open source operating system
  • Licensed under the GNU GPL v2.0
• The focus of this class

Where is Linux

• All top performing supercomputers
• Most embedded systems
• Android phones
• Almost all of the computers powering the internet
• Not many desktop systems
  • Unless you count chromebooks
• On kernel.org, freely available

Who is Linux

• Linus Torvalds
  • Created the Linux Kernel in 1991 while studying CS at the University of Helsinki as a personal project
  • Originally he supported only his own hardware.
  • “it probably never will support anything other than AT-harddisks, as that's all I have” [0]
  • Also eventually created git to act as the VCS for the kernel
• Open source community project
  • Thousands of individual contributors
  • Corporate sponsors (including Red Hat)
  • The Linux Foundation

Why use Linux

• Free software (free as in free speech)
  • No spying, telemetry, adware etc in most mainstream distributions
  • Can inspect and change the code as you please
• Fully customizable
  • Different choices for things like desktop environments, GUI programs, etc
• Can run on less powerful computers

Modularity

• An OS made from many interchangeable components
• Kernel a (relatively) small piece
• Distro <=~=> Dependency graph
• Desktop environment
• Package manager
• Default Applications

Distro vs Distro

• Difference in package naming conventions
  • libfoo-dev (apt) vs libfoo-devel (dnf)
• Difference in filesystem layout
  • Configs in different directories
  • /boot/efi/config.txt vs /boot/config.txt
• Difference in philosophy

Do anything, but by hand

source

Open Source Software as a Service

source

Beginner-friendlyish

source

Exclusively Open Source

source

System Stack Overview

Bootloader

• Grub
  

Kernel

C Standard Library

• Syscall wrappers
  • man 2 vs man 3
    

Shared Libraries

• Some examples
  

Storage Layout

File system layout (See FHS)

• / → root of file system
• /root → home folder for root account
• /bin → command binaries
• /boot → boot loader files e.g kernel, grub
• /dev → device files e.g sense-hat
• /proc → information about running processes
• /etc → configuration files
• /home → location of users’ home folders
• /lib → libraries

System Stack Overview

The future

Where will linux go from here?