The fundamental model for writing applications has not changed in 40 years. The core model is now a library of useful APIs combined with a programming language for writing applications that compose an application from the APIs and add some additional functions. There have been some changes: 1) Higher layer abstractions like BPEL or RDBMs queries. 2) More flexible “linking,” e.g. Web services. 3) Improved languages and frameworks, e.g. Spring.