+When a parameter is listed in the report but that parameter is not in the
+database or the other way around: a parameter is in the database and is not
+in the report, this constitutes a notable change in the system.
+</para>
+<para>
+Whenever the state of the system's parameters changes, Gnucomo may create
+a <emph>notification</emph>.
+Notifications are created when one of the following changes happens:
+<enumerate>
+<item>
+ A new parameter is detected. The new parameter is listed in the report
+ but is not in the database.
+</item>
+<item>
+ The value of a static property of a parameter has changed.
+</item>
+<item>
+ A value of a dynamic property of a parameter goes outside its designated range.
+</item>
+<item>
+ A non-dynamic parameter has disappeared. The parameter is in the database but
+ was not listed in the report.
+</item>
+</enumerate>
+Note that when a dynamic parameter seems to have disappeared, no notification
+will be generated.
+When a dynamic parameter is in the database but is not listed in the report,
+all properties of that parameter will be set to the default minimum value
+of the parameter's class.
+This change in the parameter's properties, however, may lead to a notification.
+As an example of a dynamic parameter, consider a process running on a system.
+The properties of a process parameter are the number of processes running and the
+amount of memory they consume, all of which are dynamic.
+The default minimum number of processes for the process parameter class is 0 (zero).
+When a process parameter is missing from a parameter report, no processes with that
+name are running.
+This may be a problem for daemons but not for most user processes.
+When a user process, for example <emph>vim</emph>, is missing from the processes report,
+its number of processes property is set to 0.
+For the <emph>vim</emph> process parameter this is well within range.
+On the other hand, when a daemon like <emph>httpd</emph> is missing from the report,
+its number of processes property will also be set to the class's minimum (0), but
+the minimum value for that parameter will probably be something like 4.
+Now, the number of processes property goes out of range, which will generate
+a notification.