TOPIC 12.1.1
History of the Object-oriented Paradigm

The concept of object oriented programming has always not been easily understood and was very slow in gaining popularity. Simula 67 created the concept of a class, so that it would have the capability for concurrency of objects rather than of tasks. Since Simula 67 also allowed a form of inheritance, it is considered the first object-oriented language.

Later, Alan Kay took the class concept of Simula 67 and made it the central concept of the Smalltalk programming language, first released in 1972. In Smalltalk, all data is contained in objects. The language was slow to catch on. However, Kay envisioned that Smalltalk would work best on a small but very powerful desktop computer. This type of computer finally began to emerge in the early 1980's. It was for this reason, and the fact that abstract data types had recently emerged in Ada and Modula-2, that attention started to be given to component reuse in terms of objects, rather than procedures.

As the popularity of the object-oriented paradigm continued to increase, designers started to add object-oriented features to existing procedural languages. In some cases, such as Turbo Pascal, the extensions were limited to a particular compiler. However, in the cases of C++ and Ada 95, the new hybrid languages have gained universal acceptance.