Rapide is a programming language framework designed for the development of large, concurrent, real-time systems by prototyping. The framework consists of a type language and default executable, speci cation and architecture languages, along with associated programming tools. We describe the main features of the type language, its intended use in a prototyping environment, and rationale for selected design decisions. 							
						
							
					 															
					Dinesh Katiyar, David C. Luckham, John C. Mitchell