Rheingold in actuality is the folder that contains the main application and data. Way back when, during the initial development of this tool, BMW used DIS (Diagnostics Information System), and as the programs evolved and due to the nature of the file naming conventions utilized by BMW, the workshop system became known as Rheingold in the enthusiast world. ISTA stands for Integrated Service Technical Application. ISTA is a workshop system that contains BMW AG Data and Information.