fix CI and fixed until C-3 3.4

book/duckietown-robotics-development/03_ros_development/02_devel_duckietown/00_devel_dt.md

@@ -508,14 +508,14 @@ Edit the `./packages/my_package/launch/multiple_nodes.launch` file to contain th
 
   <group ns="$(arg veh)">  
 
-    <node pkg="my_package" type="my_publisher_node.py" name="my_publisher_node_1" output="screen"/>
-    <node pkg="my_package" type="my_publisher_node.py" name="my_publisher_node_2" output="screen"/>
+    &lt;node pkg="my_package" type="my_publisher_node.py" name="my_publisher_node_1" output="screen"/&gt;
+    &lt;node pkg="my_package" type="my_publisher_node.py" name="my_publisher_node_2" output="screen"/&gt;
 
-    <node pkg="my_package" type="my_subscriber_node.py" name="my_subscriber_node_1"  output="screen">
+    &lt;node pkg="my_package" type="my_subscriber_node.py" name="my_subscriber_node_1"  output="screen"&gt;
         &lt;remap from="~/chatter" to="/&#36;(arg veh)/my_publisher_node_1/chatter"/&gt;
     &lt;/node&gt;
 
-    <node pkg="my_package" type="my_subscriber_node.py" name="my_subscriber_node_2"  output="screen">
+    &lt;node pkg="my_package" type="my_subscriber_node.py" name="my_subscriber_node_2"  output="screen"&gt;
         &lt;remap from="~/chatter" to="/&#36;(arg veh)/my_publisher_node_2/chatter"/&gt;
     &lt;/node&gt;
 

book/duckietown-robotics-development/03_ros_development/03_logs/00_logs.md

@@ -21,7 +21,7 @@ Robotics is innately married to hardware. However, when we develop and test our
 ## Rosbag {#rosbag}
 
 
-A bag is a file format in ROS for storing ROS message data. Bags, named so because of their `.bag` extension, have an important role in ROS. Bags are typically created by a tool like `rosbag`, which subscribes to one or more ROS topics, and stores the serialized message data in a file as it is received. These bag files can also be played back in ROS to the same topics they were recorded from, or even remapped to new topics.
+A bag is a file format in ROS for storing ROS message data. Bags, named so because of their `.bag` extension, have an important role in ROS. Bags are typically created by a tool like `rosbag`, which subscribes to one or more ROS topics, and stores the sequence of messages in a file as it is received. These bag files can be played back in ROS ith the same topics that were recorded, or even using remapping to new topics. When a bag file is replayed the temporal order of the different messages is always kept.
 
 
 Please go through [this](http://wiki.ros.org/rosbag/Commandline) link for more information.
@@ -36,7 +36,9 @@ or simply
 
     $ rosbag record -a
 
-to record all messages being published.
+to record all messages being published. 
+
+Note: Be careful on recording all the messages published in a ROS system. There might be quite a lot of topics creating very by bag files very quickly, especially using images.
 
 
 ## Rosbag Python API: Reading {#rosbag-read}