Non-GUI Client: These are applications, generate server 
requests with a minimal amount of human interaction.

GUI Clients: These are applicatoins, where occassional 
requests to the server result from a human interacting with 
a GUI (Example: Windows 3.x, NT 3.5)

OOUI clients : These are applications, which are highly-
iconic, object-oriented user interface that provides 
seamless access to information in very visual formats. 
(Example: MAC OS, Windows 95, NT 4.0)