Enterprise compute, storage, and database platforms are like rings of a tree. You add new ones each year, and they are mostly different from the last. You use whatever platform is thought to be right at the time. That’s why you have mainframes, minicomputers, client/server systems, distributed systems, and open systems, with any number of processors, databases, and security systems. So you end up with 2,000 applications and about as many connected databases that run on all types of platforms.