IBM Common User Access

Common User Access
Company type	User interface standard
Industry	Computer software, Human–computer interaction
Founded	1987; 39 years ago
Founder	IBM
Products	User interface guidelines and standards for operating systems and software

Common User Access (CUA) represents a user interface standard created for operating systems and computer programs, originally developed by IBM and released in 1987 as part of their Systems Application Architecture. Its initial deployment occurred in environments such as MVS/ESA, VM/CMS, OS/400, OS/2, and Microsoft Windows. Today, components of CUA have been integrated into other systems, including various Unix derivatives and Java platforms like the AWT and Swing.

Motivations and inspirations

The primary goal behind IBM’s creation of CUA was to establish a unified interface standard for text-based software across diverse platforms, ranging from terminals connected to mainframes to personal computers like the IBM PS/2 equipped with VGA graphics. The specification imposed rigorous guidelines on application design and behavior to bring consistency to otherwise fragmented user experiences, especially within the realm of DOS programs.

Prior to CUA’s introduction, performing basic actions such as opening a file required different key combinations depending on the software in use—WordPerfect, Lotus 1-2-3, Microsoft Word, WordStar, emacs, or vi each had their own unique commands. For instance, the help function was assigned to varying keys like or , while keys such as , , and served inconsistent roles across applications. This lack of uniformity forced users to memorize distinct interfaces for every program, hindering productivity.

The detailed CUA documentation, published in December 1987 and spanning 328 pages, shares conceptual similarities with Apple Computer’s 139-page human interface guidelines developed for the 1984 Macintosh. However, while Apple’s guidelines focused on interactive graphical software for standalone personal computers, CUA sought to retrospectively standardize interfaces across a broad spectrum of systems—from microcomputers to mainframes—and accommodate both character-based and graphical user interfaces as well as batch and interactive modes. Unlike Apple’s more design-oriented approach, CUA emphasized quantifiable standards supported by checklists to verify adherence, reflecting its extensive scope and industrial ambition.

Description

CUA establishes conventions for interface components such as dialog boxes, menus, and keyboard shortcuts that have become widely recognized—even among developers unfamiliar with the original standard.

These conventions influenced applications on Windows and DOS platforms including MS-DOS 5’s full-screen text editor edit.com. Notable features defined by CUA include:

All functions accessible via either the mouse or keyboard;
The key refreshes the display when applicable;
Menus are toggled using ;
Menus open through pressing plus the underlined letter of the menu;
Commands requiring additional input conclude with an ellipsis ("…");
Options are presented within secondary windows known as dialog boxes;
Dialog boxes use notebook-style tabs to organize sections;
Cursor keys navigate inside fields; and + switch focus between fields;
Dialogs provide 'Cancel' () and 'OK' () buttons to either discard or confirm changes;
Online help can be accessed via a Help menu or context-sensitive ;
The first menu is labeled 'File' (containing new, open, save, quit); followed by 'Edit' (undo, redo, cut, copy, delete, paste);
Cut: +; Copy: +; Paste: +;
Windows can be resized by dragging any of their eight border segments.

CUA forms the foundation not only for DOS but also for Windows’ Consistent User Interface (CUI), OS/2 applications—including both text-based and Presentation Manager graphical interfaces—and IBM mainframe systems adhering to Systems Application Architecture.

Beyond standardizing DOS software, CUA sought to align software behavior and hardware functionality throughout IBM’s entire computing range from microcomputers up to mainframe environments.

The third edition introduced an object-oriented workplace, shifting emphasis away from applications toward working directly with data objects like documents and images. This approach matched user expectations by focusing interaction on documents through programs rather than controlling applications explicitly, thereby simplifying usability. (See also object-oriented user interface.)

Influence

The Common User Access (CUA) framework played a notable role in shaping early versions of Microsoft Windows during the collaboration between IBM and Microsoft on the OS/2 Presentation Manager. Nonetheless, subsequent IBM updates to CUA were not integrated by Microsoft, which diminished CUA's influence on Windows development; Windows instead introduced distinct elements such as the Start menu. Despite this, numerous standard keyboard shortcuts and graphical user interface components originating from CUA continue to be part of Windows, including the widely used shortcut for closing windows.

While CUA's impact on Unix terminal-based applications was minimal, it significantly affected Unix graphical user interfaces. Prominent Unix widget toolkits like Motif and the CDE explicitly aimed for compatibility with CUA guidelines. Today’s predominant Unix desktop environments, including GNOME and KDE, adhere extensively to CUA principles. The portion of CUA implemented in both Microsoft Windows and OSF/Motif is frequently recognized as a de facto standard for contemporary Unix GUI design practices.

References

IBM, Systems Application Architecture: Common User Access: Panel Design and User Interaction, Document SC26-4351-0, 1987.
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 SC26-4583-00, 1992. (Partial archive)
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
Object-oriented interface design: IBM common user access guidelines. Que, 1992.

External links

Common User Access – A consistent and usable human-computer interface for the SAA environments, by Richard E. Berry, IBM Systems Journal, Vol. 27, No. 3, 1988. PDF available via web archive.
The evolution of the Common User Access Workplace Model, by Richard E. Berry & Cliff J. Reeves, IBM Systems Journal, Vol. 31, No. 3, 1992.
The designer's model of the CUA workplace, by Richard E. Berry, IBM Systems Journal, Vol. 31, No. 3, 1992.
IBM BookManager SAA CUA bookshelf 1992
CUA Window Emulation for SlickEdit – chart of CUA-based shortcut keys provided through a SlickEdit mode