Error and progress messages to the user are sent via the talker. It is unwise to run the system with no talker visible: you might miss important information.
Colour coding is used to distinguish messages of different urgency.
The most urgent messages are displayed in a flashing, beeping alarm window
and require the user to acknowledge the alarm. Commands on the Filtering
menu can be used to extend or restrict the set of messages that are displayed.
You can run any reasonable number of talkers in parallel. "Reasonable" is loosely defined, but up to five talkers per system should be no problem.
The talker is actually showing you the contents of a log file. If you need to make a fault report, you need not copy out the full error messages because the support staff can get them from the log.
The details of the talker are discussed further in document OBS-TALK-4.