Difference Between Single And Multiple Document Interface (MDI vs SDI

A Single Document Interface (SDI) and a Multiple Document Interface (MDI) are two different approaches to designing graphical user interfaces for applications. These two approaches offer unique ways of presenting and managing documents within an application, each tailored to specific scenarios and user needs. Let us look at how they differ from one another:

What Is 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 manger handles separately. In other words, it is a type of application that deal with a single document and single view of the document at one point of time.

A window does not have a ‘’ background’’ or ‘’parent’’ window containing its menu or toolbar; instead each window contains its own menu or toolbar. There is no way to open another document in the same application, the only way is to launch another instance of the application and open another document.

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. Notepad and wordpad are such applications in windows.

SDI can be more useful in cases where users switch more often between separate application than among the windows of one application.

Also Read: Difference Between Spreadsheet And Worksheet

What Is Multiple-Document Interface (MDI)?

A multiple-document interface is a graphical user interface in which multiple windows reside under a single parent window. Such systems often allow child windows to embed other windows inside them as well, creating complex nested hierarchies.

Each document in a multiple-document interface (MDI) application is displayed is displayed in a separate child window within the client area of the application’s main window. Typical MDI applications include word-processing applications that allow the user to work with multiple text documents and spreadsheet applications that allow the user to work with multiple charts and spreadsheets.

An MDI application has three kinds of windows: a frame window, an MDI client window, as well as a number of child windows. The frame window is like the main window of the application: it has a sizing border, a title bar, a window menu, a minimize button, and a maximize button. The application must register a window class for the frame window and provide a window procedure to support it. 

One of the major drawbacks of MDI is that, MDI can make it more difficult to work with several applications at once by restricting the ways in which windows from multiple applications can be arranged together without obscuring each other.

Also Read: Difference Between XLS And XLSX

Difference Between Single And Multiple Document Interface In Tabular Form

Description MDI is a type of graphic user interface which is able to show more than a single document at a time on the screen.   SDI is a Graphic User Interface which is able to show one document at a time on the screen.  
Limits Child windows per documents are allowed in MDI.   One document per window is enforced in SDI.  
Container Control MDI is a container control.   SDI is not a container control.  
Operation MDI contains multiple documents which at a time appear as child window.   SDI contains one window only at a time.  
Interface MDI supports many interfaces which means you can handle many applications at a time according to user’s requirement.   SDI supports one interface which means you can handle only one application at a time.  
Switching Between Documents For switching between documents MDI uses special interface inside the parent window.   For switching between documents SDI uses Task Manager for that.  
Grouping In MDI grouping is implemented naturally.   SDI grouping is possible through special window managers.  
Maximizing Documents For maximizing documents, parents window is maximized by MDI.   For maximizing documents, parent windows are maximized through a special code or window manager.  
Flexibility Switching focus to the specific document can be easily handled by MDI.   Switching focus to specific document is difficult to implement in SDI.  

MDI vs SDI: Key Takeaways


  • SDI: In an SDI, each instance of the application represents a single document window. Each document window operates independently of others.
  • MDI: In an MDI, the application can have multiple document windows (child windows) within a single parent window. The parent window provides a container for managing and organizing multiple documents.

Window Management

  • SDI: Each document in SDI mode has its own independent window with separate controls for each.
  • MDI: In MDI, all documents are contained within the same parent window. This can help in efficient window management, especially when dealing with a large number of documents.

User Experience

  • SDI: Generally provides a simpler and more straightforward user experience, suitable for applications where users mainly work with one document at a time.
  • MDI: Offers a more complex user experience but can be beneficial for applications where users need to switch between multiple documents quickly.

Resource Usage

  • SDI: Each document window in SDI mode consumes its own system resources, which can lead to higher memory and CPU usage when dealing with multiple documents.
  • MDI: Since all documents share the same parent window, resource usage can be more optimized, resulting in potentially lower memory and CPU consumption.

Interface Complexity

  • SDI: Generally has a simpler interface since each document has its own window and controls.
  • MDI: Can be more complex due to the need for managing multiple documents within the same parent window, including features like tabbed navigation or document list panes.

Context Switching

  • SDI: Context switching involves switching between different application instances, which can be relatively slower.
  • MDI: Context switching is usually faster within an MDI application as it involves switching between child windows within the same parent window.

Document Isolation

  • SDI: Offers better document isolation since each document is in a separate window, reducing the risk of unintended interactions.
  • MDI: Documents within an MDI application are within the same parent window, which might lead to more potential for unintended interactions.

Task Organization

  • SDI: Well-suited for single-tasking scenarios, where the user primarily focuses on one document at a time.
  • MDI: Effective for multitasking scenarios, where users need to work with multiple documents simultaneously.

Screen Space Usage

  • SDI: Can potentially use more screen space due to the presence of separate windows for each document.
  • MDI: Utilizes screen space more efficiently, especially when handling multiple documents, as they are contained within a single parent window.

Development Complexity

SDI: Generally simpler to develop, as each document operates independently.

MDI: Requires more complex coding and design to manage child windows, document interactions, and parent window features.

Leave a Comment