Unit 1: What ROS 2 Is

Before you install anything, you need a map.

ROS 2 can look ridiculous the first time you see it because five different things get called "ROS" in the same conversation: the software distribution, a package, a node, the command line, and sometimes the whole robot.

This Unit separates those layers before you start typing commands.

Unit question

What problem does ROS 2 solve, and what pieces should you be able to point to in a running system?

By the end of the Unit, you should be able to explain this without hand-waving:

UBUNTU
  ↓ hosts
ROS 2 JAZZY INSTALLATION
  ↓ provides packages + tools + libraries
PACKAGES
  ↓ provide executables
EXECUTABLES
  ↓ create
NODES
  ↓ communicate inside
THE ROS GRAPH

Diagrams open at a readable shape-aware scale. Zoom or expand when you need more detail.

You are not memorizing vocabulary for a quiz. This map becomes the troubleshooting model for the rest of the course.

Evidence gate

Move on when you can draw the stack above, explain each layer in your own words, and answer one question:

If ros2 node list fails because the ROS environment was never sourced, which layer is broken: the node, the package, or the shell environment?

Source attribution: adapted from the ROS 2 Jazzy documentation in Gh0stlyKn1ght/ros2_documentation at commit 32100a2d033187923ae57035941586e1b9a9e595, licensed CC BY 4.0. Robotnix reorganizes and rewrites the material for this self-paced student course.