Single document interface

In graphical user interfaces, a single document interface or SDI is a method of organizing graphical user interface applications into individual windows that the operating system's window manager handles separately. Each window contains its own menu or tool bar, and does not have a "background" window or "parent" window containing its menu or tool bar. Applications which allow the editing of more than one document at a time, e.g. word processors, may therefore give the user the impression that more than one instance of an application is open.

Often, each window is represented as an individual entry in the operating system's task bar or manager. Some task managers summarize windows of the same application. For example, Mac OS X uses a feature called Exposé which allows the user to temporarily see all windows belonging to a particular application.