IBM Common User Access

CUA (Common User Access, Eng. General for common user access ) is one of the company IBM in 1987 as part of the SAA Specifications established in 1989 a guideline for the design of user interfaces of computer programs. These guidelines were originally in the operating systems OS / 2 (then jointly developed by IBM and Microsoft) applied and Microsoft Windows. Parts of the CUA standards are now implemented in programs for other operating systems such as Mac OS X, Unix and the libraries Java AWT and Java Swing.

The CUA standards include guidelines for the use of dialog boxes, menus, and keyboard shortcuts. These guidelines are so influential that even orient programmers thereto which have never read the CUA standard.

In this Directive, inter alia, Predefined shortcut keys to quickly access features of the programs. For example, many keyboard shortcuts (Alt F4, Ctrl Insert ⇧ F10) attributed the Microsoft Windows operating system to this Directive.

Defined standards

Some of the standards can be found in Windows itself and DOS -based applications such as the text editor included in DOS for MS- DOS 5. These are for example:

  • A menu bar at the top of the screen
  • All operations can be carried out with either the mouse or the keyboard.
  • Menus can be called directly with a highlighted letter in the menu name by combining the Alt key, Alt alone invokes the menu itself on.
  • Menu commands that require additional information, indicate this by a trailing ellipsis operator ( "...").
  • Options are set in dialog boxes.
  • Navigation within the fields of a dialog window is by cursor keys, between the fields can by Tab and Shift Tab ( ​​backward jump ) to jump.
  • Dialog box should have a Cancel button that can be activated by the Esc key and discards any changes. A Ok button, which should be available via Enter key is also part of the standard.
  • The program is an online help have a Help menu item as the last item on the menu bar.
  • Context-sensitive help should be accessible via the F1 key.
  • The first menu item is called "File" and operations for working with files, to exit the program, and so forth. The next menu item is called " Edit" and include Cut, Copy, and Paste commands. The third menu item should be " View".
  • The keyboard shortcut for Cut is ⇧ Delete, Copy and Paste is Ctrl Ins Ins is ⇧.
  • 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 imposes strict rules about on how applications should look and function. The goal was to unify MS -DOS-based applications, as these until then had very different user interfaces.


  • In WordPerfect, the command was F7 to open a file, third
  • In Lotus 1-2-3 files were opened by the following sequence: / ( to bring up the menu ), W ( for workspace), R ( for Retrieve, dt pick ).
  • In Microsoft Word 5 files were opened on this key sequence: Esc (to access the menus ), T ( for transfer) L (for charging).
  • In WordStar it was Ctrl K O.
  • In emacs files using Ctrl X followed by Ctrl f ( for Find -File, dt seeking file) open.

Some programs use the Esc key to cancel an action, others a complete normally. WordPerfect used them as repeat signs. Some programs use the End key to jump to the end of the line, others to complete filling out a form. F1 was usually help, but in WordPerfect it was F3. The Ins key is usually used to switch between insert and overwrite mode, but there were also programs that so pasted the contents of the clipboard into the active document.

This had to be learned individually each program and its user interface. One was an expert if you had learned to use the user dozens of programs, because a user who encountered a new program, could his previous knowledge of similar applications not usually apply.


The specifications have been heavily influenced by Apple's Human Interface Guidelines detailed. These were published in the form of a book that specifies exactly look like software for the Apple Macintosh, and has to work. When this work was published, the Mac was just as new graphical user interfaces. Therefore, Apple went to great efforts to ensure that applications follow a uniform appearance. CUA had similar goals, but the problem is that such guidelines should be applied to the existing programs of a heterogeneous industrial sector.

However, CUA covered not only DOS applications, it is also the standard by which the Windows user interface was designed and also OS/2-Anwendungen, both text mode and the " Presentation Manager " surface. Even IBM mainframe followed the standards of the Systems Application Architecture (SAA). Therefore, CUA is more than just an attempt to unify DOS applications. CUA was part of a broader objective to unify the functions of all IBM software across the entire IBM computer product range and to rationalize. The extended from the micro computers to mainframes, their user interfaces, functionality to the communication protocols and the type of data storage. Since also affected PC-compatible computer, it comprised the entire PC industry, which is perhaps one of the reasons why the goal was not completely achieved.

The third edition of CUA differed by the introduction of object-oriented workplace (english desktop) fundamentally from the first two editions. This changed the view of how the user dealt with data. Way from the application-centric view towards a vision oriented documents with the aim to make the system easier usable.

The concept of the workplace was implemented in 1995 by Microsoft in Windows 95. Critical here was the introduction of the Start menu, which decreased strongly the emphasis on the object-oriented desktops.


  • 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.
  • IT standard
  • Graphical User Interface