System Object Model

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What Does System Object Model Mean?

System Object Model (SOM) is an object-oriented library packaging technology developed by IBM that allows various programming languages to share class libraries, regardless of the language in which they were originally written.


The most widespread use of SOM within IBM is in OS/2 and Workplace Shell. Other implementations of SOM include Unix, Windows and Mac. However, the active development of this technology ended in the mid-’90s, around the time that Apple withdrew its support and development resources.

Techopedia Explains System Object Model

System Object Model was intended to be used as a solution to many of the interoperability and reuse problems that occur while sharing class libraries between object-oriented and non-object-oriented languages. SOM was designed to be used across IBM’s mainframe computers and desktops. It serves as an object-oriented model that can be distinguished from other models contained in object-oriented programming languages. SOM basically includes an interface definition language, a runtime environment with procedure calls and a set of enabling frameworks.

SOM was originally a technology developed for IBM’s range of computers and desktops, but eventually came to be used by other companies, which extended its benefits to different software environments.

Some of the important characteristics of SOM include:

  • SOM allows for the creation of portable shrink-wrapped libraries.
  • The class libraries can be created in a particular language, which can be accessed and used by other languages.
  • New methods can be added to existing methods without requiring the recompilation of the application.
  • SOM works with procedural programming languages.
  • SOM provides an object model for non-object-oriented languages.
  • SOM allows for the addition of new classes to the inheritance hierarchy without having to recompile the application.

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.