feat(lab02): add exercice 3

doc/lab-01_02.typ

@@ -209,8 +209,28 @@ mymodule 16384 0 - Live 0xffff8000011bf000 (O)
   ],
 )
 
+//-------------------
+// Exercise 3: What does it mean the 4 values in ```/proc/sys/kernel/printk``` ?
+//-------------------
+#task(
+  [What does it mean the 4 values in ```/proc/sys/kernel/printk``` ?],
+  [
+    ```bash
+    |> cat /proc/sys/kernel/printk
+    7	4	1	7
+    ```
+    The number specified the level of output in a console.
 
+    This file specifies the log level for:
+    - current: 7
+    - default: 4
+    - minimum: 1
+    - boot-time-default: 7
 
+    This number matches with this table (#link("https://www.kernel.org/doc/html/latest/core-api/printk-basics.html", [printk documentation])):
+    #image("resources/img/printk-log-levels.png")
+  ]
+)
 
 
 //-------------------------------------