The System Object Model (SOM) is IBM's object-oriented programming model which provides you language-neutral object-oriented programming mechanisms, a set of run times for the support and management of objects, frameworks for the implementation of classes and objects, and tools for associated application development.

Workplace Shell is the OS/2 user interface and is implemented by using the SOM functions, methods, and structures. SOM's run-time support is what allows Workplace Shell applications to run on different levels of the operating system without having to be recompiled.

Object-oriented programming is a programming paradigm based on objects, which are programming constructs designed to reflect items in the real world. An object consists of both the data necessary to describe a real-world item and the functions necessary to describe the behavior of the item. This is in contrast to the structured programming model, which focuses on things that can be done to the data (the functions) and which treats the data only as something to be acted on. Objects bind together the data that describes an item and the functions that act on the data. The data is called the object's state. The functions that define the object's behavior are called methods. Objects are instances, or instantiations of a class. A class is a description of an object. It defines the data that represents the object's state and the methods that the object supports.

SOM is designed specifically to support the new, object-oriented paradigm, and to be usable with both procedural (non-object-oriented) languages and object-oriented languages. SOM is not a language-it is a system for defining, manipulating, and releasing class libraries. SOM is used to define classes and methods, while permitting you to choose a language for implementing these methods. Therefore, you will be able to use SOM quickly without having to learn a new language syntax. SOM consists of a run-time library and a set of utility programs that support building, externalizing, and manipulating software objects.

SOM objects are language-neutral. They can be defined in one programming language and used by applications or objects written in another programming language.