EME is Enterpise Meta Environment which is repository(stores data). GDE is Graphycal Development Environment which is user's work area(develops Graphs) and Co-Ops is used to run the developed graphs. With out Co-Ops we can't run graphs. and we can install Co-Ops in Unix or Windows NT or any other OS.
EME is said as enterprise metdata env, GDE as graphical devlopment env and Co-operating sytem can be said as asbinitio server.
Co operating system is the Abinitio Server. this co-op is installed on perticular O.S platform that is called NATIVE O.S .comming to the EME, its i just as repository in informatica , its hold the metadata,trnsformations,db config files source and targets informations. comming to GDE its is end user envirinment where we can devlop the graphs(mapping just like in informatica)
desinger uses the GDE and designs the graphs and save to the EME or Sand box it is at user side.where EME is ast server side.