User-written software is software written by users. Typically, "user-written software" refers to add-ons to a software package written by its users, often customers of the company that sells the package. User-written software is part of a larger phenomenon of widespread non-professional software development.

Common examples of user-written software include the following:

• Scripts, macros, etc.: Advanced word processors, spreadsheets, and other large packages, often include built-in programming languages. These allow end users to build on the package and expand its capabilities to meet specific needs.
• Small programs: Businessmen, engineers, and scientists write simulations to demonstrate or test specific theories. In recent years, Microsoft's Visual Basic has been commonly used in this way.
• Animation scripts: Graphic artists write scripts that describe characters and envirnoments and how the characters move to produce the intended animation.
• Configuration files: Configuration files blur the line between programs and data, but many configuration files can be interpreted as programs. For example, email filters are sequenced lists of criteria and actions to take.
• Game modifications: Users modify computer games, introducing their own characters, environments, etc. Many recent games are distributed with modification in mind. In the gaming community, these modifications are knows as mods.

In recent years, the rise of open source development models has blurred the distinction between user-written software and other software. In many open-source projects, users of a software package may contribute their own code for inclusion in the package. In some cases, they can also join as full-fledged developers.

By Dr. BMC.

See also: software engineering

Software development