# Hello Linux

### FLUG Presentation

April 3, 2026

## What is a computer?

## The kernel

- Kernel loads data from RAM to CPU
- Kernel decides who gets to run on CPU
- Kernel knows how to talk with HDD and other devices

## Linux is a kernel

There are others, including:

- Windows NT (Windows)
- XNU (macOS / iOS)
- BSD (FreeBSD, OpenBSD, NetBSD)

## Linus Torvalds

## Kernel vs userspace

- Kernel Space
  - Core operating system
  - Unrestricted access to hardware and memory
  - Runs in privileged mode
- User Space
  - Where user applications run (e.g., your browser)
  - Restricted access (must ask kernel for resources)
  - Communicates with kernel via System Calls

## Userspace -- GNU

- GNU's Not Unix!
- Started in 1983 by Richard Stallman to create a free operating system
- Provides core user utilities (Coreutils) like `ls`, `cp`, and `rm`
- Provides the standard shell (Bash) and compiler (GCC)
- Provides the C Library (glibc) which acts as the bridge between user space and the kernel
- This is why the complete OS is often referred to as GNU/Linux!

## Richard Stallman

## Free Software vs Open Source

- Free Software (Stallman/FSF)

  Focuses on ethics and user freedom. "Free as in speech, not free as in beer."

- The Four Freedoms:
  - 0. Run the program for any purpose.
  - 1. Study and change the source code.
  - 2. Redistribute exact copies.
  - 3. Distribute modified versions.

## Free Software vs Open Source

- Open Source

  Focuses on practical benefits (building better software through collaboration).

## OK; so you have GNU/Linux

## Display Servers: Xorg & Wayland

- Xorg (X11): The traditional display server. Extremely compatible, but burdened by decades of legacy code.
- Wayland: The modern replacement protocol. Designed to be simpler, more secure, and tear-free. Now the default on most modern distros.

## Desktop Environments

Often what users interact with directly. They provide the graphical interface, window management, panels, and bundled applications.

## GNOME

## KDE Plasma

## More software

You need more than just a pretty desktop; you need usefull applications!

- Most browsers (Chrome, Firefox, Safari) work in Linux
- There are many open-source Linux-native tools, like LibreOffice
- ... and we can run Windows applications using WINE

## Package Managers

- Like an App Store, but built for the command line (and much older).
- Automates installing, upgrading, configuring, and removing software.
- Resolves dependencies (if App A needs App B, it installs B automatically).
- Examples: `apt` (Debian/Ubuntu), `pacman` (Arch), `dnf` (Fedora).

## Linux distributions

So many choices! Distros make some of these decisions for you. They bundle a package manager, display manager, configuration files, etc for you.

- Debian-based (Ubuntu)
- Arch-based (Arch, Manjaro, CachyOS)
- Redhat (Fedora, RHEL)
- Gentoo (no.)

## Try things out

You run Linux on your computer without installing it. Try out a few different window managers and distributions.

Today, I recommend trying CachyOS

- It feels snappy
- Has lots of desktop environments
- One of the best package managers

## CachyOS - KDE Plasma

## CachyOS - i3

## CachyOS - Niri

## CachyOS - Qtile

## CachyOS - Wayfire

## But.. why?

## Thank You

Questions?