Single document interface

SDI applications allow only one open document frame window at a time. An example of this would be a simple text document(Notepad).

MDI applications allow multiple document frame windows to be open in the same instance of an application. An MDI application has a window within which multiple MDI child windows, which are frame windows themselves, can be opened, each containing a separate document. In some applications, the child windows can be of different types, such as chart windows and spreadsheet windows. In that case, the menu bar can change as MDI child windows of different types are activated.

https://msdn.microsoft.com/en-us/library/b2kye6c4.aspx

See also

• Graphical user interface
• Comparison of document interface
• Multiple document interface
• Tabbed document interface
• IDE-style interface