" What does "event driven" mean? Was there ever an application which did not respond to user events. . ? Just because an application responds to events does not mean it is "event driven". Event driven means it spends much of its time waiting for an event and then takes action if and when an event occurs. Contrast this with some programs that do not respond to events at all, but simply do their job and terminate. For example, an operating system command to display the current time. It displays the time and is done; it does not wait for events. Rc Model Boat For more information, see: Event-driven_programming Implementations The pattern was first described in 1979 by Trygve Reenskaug, then working on Smalltalk at Xerox research labs. This original implementation inspired many other GUI frameworks such as: The NeXTSTEP and OPENSTEP development environments encourage the use of MVC. "

" The first theory of this kind was proposed in 1974 by Georgi and Glashow, using SU(5) as the unifying group. A distinguishing characteristic of these GUTs is that, unlike the Standard model, they predict the existence of proton decay. In 1999, the Super-Kamiokande neutrino observatory reported that it had not detected proton decay, establishing a lower limit on the proton half-life of 6. 7× 1032 years. This and other experiments have falsified numerous GUTs, including SU(5). Another effort to address the first defect has been to develop Preon models which attempt to set forth a substructure of more fundamental particles than those set forth in the Standard Model. In addition, there are cosmological reasons why the standard model is believed to be incomplete. Model Boat Kit Within it, matter and antimatter are symmetric. While the preponderance of matter in the universe can be explained by saying that the universe just started out this way, this explanation strikes most physicists as inelegant. "