Unit Check: Explain the ROS 2 Stack

No installation yet.

First prove that you know what you are about to install.

Build the map

Create a diagram containing all of these layers:

Ubuntu 24.04
ROS 2 Jazzy installation
package
executable
node
ROS graph
interface / communication

Connect them with verbs.

Example:

package
  -- provides -->
executable

Do not submit a pile of disconnected boxes.

Explain one real path

Use Turtlesim as the example even though you have not run it yet:

turtlesim package
  ↓
turtlesim_node executable
  ↓
/turtlesim node
  ↓
ROS graph connections

Then answer:

1. What does Ubuntu provide that ROS 2 depends on?
2. What does a ROS 2 package organize?
3. What is the difference between an executable and a node?
4. What does the ROS graph represent?
5. Why is Jazzy fixed as the course distro?

Failure reasoning

Someone opens a terminal after installing ROS 2 and types:

ros2 node list

The shell responds:

ros2: command not found

Which explanation is stronger?

A. The robot node crashed.

B. The shell may not have the ROS 2 environment sourced, so the ros2 command itself is not available in that environment.

Choose one and explain why.

Ready for Unit 2

You are ready when you can explain this chain without reading it:

Ubuntu
→ ROS 2 distribution/environment
→ packages/executables
→ running nodes
→ ROS graph
→ communication interfaces

Unit 2 turns that model into a real Ubuntu installation.