Common User Access

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CUA ( Common User Access ) is a guideline for the design of user interfaces for computer programs that has been defined by IBM since 1987 as part of the 1989 SAA specifications . These guidelines were originally used in the operating systems OS / 2 (at that time still developed jointly by IBM and Microsoft ) and Microsoft Windows . Parts of the CUA standard have now also been implemented in programs for other operating systems such as Mac OS X , Unix and the Java AWT and Java Swing libraries .

The CUA standards contain guidelines for the use of dialog boxes, menus and keyboard shortcuts. So influential are these guidelines that even programmers who have never read the CUA standard will orient themselves by them.

This guideline may include a. Preset keyboard shortcuts for quick access to program functions. So are z. For example, many key combinations ( Alt+ F4, Strg+ Einfg, + F10) in the Microsoft Windows operating system are due to this policy.

Defined standards

Some of the standards can be found in Windows itself and in DOS- based applications such as the MS-DOS Editor . These are z. B .:

  • a menu bar at the top of the screen
  • all operations can be performed with both the mouse and the keyboard.
  • Menus can be called up directly by combining the Alt key with a highlighted letter of the menu name; Alt alone calls up the menu itself.
  • Menu commands that require further information indicate this with a trailing ellipsis operator ("...").
  • Options are set in dialog boxes.
  • Navigation within the fields of a dialog window is carried out using the cursor keys; you can jump between the fields using the tab key and shift key + tab key (jump backwards).
  • Dialog windows should have a cancel Escbutton that can be activated by pressing the button and discards all changes. An OK button, which should be accessible via the enter key, is also part of the standard.
  • The program should have online help with a help menu item as the last item on the menu bar.
  • Context-sensitive help should be F1accessible via the key.
  • The first menu entry should be called “File” and contain operations for working with files, for exiting the program and so on. The next menu item should - if one is required - be called "Selection". The following menu item should be called "Edit" and contain cut, copy and paste commands. The third menu item should be called "View".
  • The keyboard shortcut for cut is + Entf, copy is Strg+, Einfgand paste is + Einfg.
  • The size of a window can be changed by dragging one of the 8 segments of the window frame.

CUA is a detailed specification and has strict rules about how applications should look and function. The aim was to standardize MS-DOS-based applications, as they had previously had very different user interfaces.


  • In WordPerfect , the command was to open a file F7, 3.
  • In Lotus 1-2-3 files were opened by the following sequence: /(to call up the menus), W(for workspace ), R(for Retrieve ).
  • In Microsoft Word 5, files were opened using this key sequence: Esc(to bring up the menus), T(for transfer ) L(for load).
  • In WordStar it was Strg+ K+ O.
  • In emacs , files are opened using Strg+ Xfollowed by Strg+ f(for Find-File ).

Some programs used the Esckey to cancel an action, others to complete an action normally. WordPerfect used them as a repeat character. Some programs used the Endekey to jump to the end of a line, others to complete a form. F1was mostly of help, but in WordPerfect it was F3. The Einfgkey was mostly used to switch between insert and overwrite mode, but there were also programs that used it to insert the contents of the clipboard into the active document.

As a result, each program and its user interface had to be learned individually. You were considered an expert when you had learned to use the user interfaces of dozens of programs, because a user who encountered a new program was usually unable to apply his previous knowledge of similar applications.


The specifications were heavily influenced by Apple's detailed Human Interface Guidelines . These were published in the form of a book that specifies exactly how software for the Apple Macintosh should look and work. When this work appeared, the Mac was new, as was graphical user interfaces. As a result, Apple went to great lengths to ensure that applications followed a consistent look. CUA had similar goals, but the problem that such guidelines should be applied to existing programs in a heterogeneous industry.

However, CUA not only covered DOS applications, it is also the standard by which the Windows user interface was designed and also OS / 2 applications, both text mode and the Presentation Manager interface . IBM mainframes also followed the standards of the Systems Application Architecture (SAA). Therefore, CUA is more than just an attempt to standardize DOS applications. CUA was part of the larger goal of standardizing and streamlining the functionality of all IBM software across the entire IBM computer lineup. This ranged from the microcomputers to the mainframe computers, their user interfaces, functionality to the communication protocols and the type of data storage. Since this also affected PC-compatible computers, it encompassed the entire PC industry, which is perhaps one of the reasons why the goal was not fully achieved.

The third edition of CUA differed fundamentally from the first two editions due to the introduction of the object-oriented workstation (English desktop ). That changed the way the user looked at data. Away from the application-centered view towards a document-oriented view with the aim of making the system easier to use.

The concept of the workplace was implemented in Windows 95 by Microsoft in 1995 . The introduction of the start menu , which greatly reduced the emphasis on the object-oriented desktop, was critical .


  • IBM, Systems Application Architecture: Common User Access: Panel Design and User Interaction , Document SC26-4351-0, 1988.
  • IBM, Systems Application Architecture: Common User Access: Advanced Interface Design Guide , Document SC26-4582-0, 1990.
  • IBM, Systems Application Architecture: Common User Access: Basic Interface Design Guide , Document SC26-4583-0, 1990.
  • IBM, Systems Application Architecture: Common User Access: Guide to User Interface Design , Document SC34-4289-00 1991.
  • IBM, Systems Application Architecture: Common User Access: Advanced Interface Design Reference , Document SC34-4290-00 1991.

Individual evidence