Common User Access
Encyclopedia
Common User Access is a standard for user interface
s to operating system
s and computer program
s. It was developed by IBM
and first published in 1987 as part of their Systems Application Architecture
. Used originally in the OS/MVS, VM/CMS, OS/400
, OS/2
and Microsoft Windows
operating systems, parts of the CUA standard are now implemented in programs for other operating systems, including variants of Unix
. It is also used by Java AWT
and Swing
.
applications, which until then had independently implemented different user interfaces.
Examples:
Some programs used to cancel an action. while some used it to complete one; WordPerfect used it to repeat a character. Some programs used to go to the end of a line, while some used it to complete filling in a form. was often help, but in WordPerfect, help was on instead. sometimes toggled between overtype and inserting characters, but some programs used it for "paste".
Thus, every program had to be learned individually and its complete user interface memorized. It was a sign of expertise to have learned the UIs of dozens of applications, since a novice user facing a new program would find their existing knowledge of a similar application absolutely no use whatsoever.
The detailed specification drew some of its inspiration from Apple Computer
's lavishly detailed human interface guidelines
. The Apple HIG is a detailed book specifying exactly how software for the Apple Macintosh computer should look and function. When it was first written, the Mac was new, and Graphical user interface
(GUI) software was a novelty, so Apple took great pains to ensure that programs would conform to a single shared look and feel. CUA had a similar aim, but it faced the more difficult task of trying to impose this retroactively on an existing, thriving but chaotic industry, with the much more ambitious goal of unifying all UI— from personal computers to minicomputers to mainframes; and supporting both character and GUI modes; and both batch and interactive designs. By comparison, the Apple HIG only supported Interactive GUI on a single personal computer.
es, menu
s and keyboard shortcut
s that have become so influential that they are implemented today by many programmers who have never read the CUA.
Some of these standards can be seen in the operation of Windows itself and DOS-based applications like the MS-DOS 5 full-screen text editor
edit.com. CUA hallmarks include:
CUA not only covered DOS applications, but was also the basis for the Windows Consistent User Interface standard (CUI), as well as that for OS/2 applications — both text-mode and the Presentation Manager
GUI — and IBM mainframes which conformed to the Systems Application Architecture
.
CUA was more than just an attempt to rationalise DOS applications — it was part of a larger scheme to bring together, rationalise and harmonise the overall functions of software and hardware across IBM's entire computing range from microcomputers to mainframes. This is perhaps partly why it was not completely successful.
The third edition of CUA took a radical departure from the first two by introducing the object-oriented workplace
. This changed the emphasis of the user's interactions to be the data (documents, pictures, and so on) that the user worked on. The emphasis on applications was removed with the intention of making the computer easier to use by matching users' expectations that they would work on documents using programs (rather than operating programs to work on documents). (See also object-oriented user interface
.)
operating system during the period of joint IBM and Microsoft cooperation on OS/2 Presentation Manager. But later releases of IBM's CUA documents were not used for Microsoft products, and so CUA became less significant in the Windows environment. For instance, the Start menu
was introduced, which removed the emphasis on an object-oriented desktop. Most of the standard keystrokes and basic GUI widgets specified by the CUA remain a feature of Windows, but few users are aware of them.
CUA has never had significant impact on Unix
terminal (character-mode) applications. However, all major Unix GUI environments/toolkits (whether or not based on the X Window System
) have featured varying levels of CUA compatibility, with Motif/CDE
explicitly featuring it as a design goal. The current major environments, GNOME
and KDE
, also feature extensive CUA compatibility. The subset of CUA implemented in Microsoft Windows
or OSF/Motif is generally considered a de-facto standard to be followed by any new Unix GUI environment.
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...
s to operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s and computer program
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
s. It was developed by IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
and first published in 1987 as part of their Systems Application Architecture
Systems Application Architecture
Systems Application Architecture is a set of standards for computer software, developed by IBM in the 1980s and implemented in IBM operating systems including MVS, OS/400 and OS/2...
. Used originally in the OS/MVS, VM/CMS, OS/400
OS/400
IBM i is an EBCDIC based operating system that runs on IBM Power Systems. It is the current evolution of the operating system named i5/OS which was originally named OS/400 when it was introduced with the AS/400 computer system in 1988....
, OS/2
OS/2
OS/2 is a computer operating system, initially created by Microsoft and IBM, then later developed by IBM exclusively. The name stands for "Operating System/2," because it was introduced as part of the same generation change release as IBM's "Personal System/2 " line of second-generation personal...
and Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
operating systems, parts of the CUA standard are now implemented in programs for other operating systems, including variants of Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
. It is also used by Java AWT
Abstract Window Toolkit
The Abstract Window Toolkit is Java's original platform-independent windowing, graphics, and user-interface widget toolkit. The AWT is now part of the Java Foundation Classes — the standard API for providing a graphical user interface for a Java program.AWT is also the GUI toolkit for a...
and Swing
Swing (Java)
Swing is the primary Java GUI widget toolkit. It is part of Oracle's Java Foundation Classes — an API for providing a graphical user interface for Java programs....
.
Motivations and inspirations
CUA was a detailed specification and set strict rules about how applications should look and function. Its aim was in part to bring about harmony among DOSDOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
applications, which until then had independently implemented different user interfaces.
Examples:
- In WordPerfectWordPerfectWordPerfect is a word processing application, now owned by Corel.Bruce Bastian, a Brigham Young University graduate student, and BYU computer science professor Dr. Alan Ashton joined forces to design a word processing system for the city of Orem's Data General Corp. minicomputer system in 1979...
, the command to open a file was , . - In Lotus 1-2-3Lotus 1-2-3Lotus 1-2-3 is a spreadsheet program from Lotus Software . It was the IBM PC's first "killer application"; its huge popularity in the mid-1980s contributed significantly to the success of the IBM PC in the corporate environment.-Beginnings:...
, a file was opened with (to open the menus), (for Workspace), (for Retrieve). - In Microsoft WordMicrosoft WordMicrosoft Word is a word processor designed by Microsoft. It was first released in 1983 under the name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS , the Apple Macintosh , the AT&T Unix PC , Atari ST , SCO UNIX,...
, a file was opened with (to open the menus), (for Transfer), (for Load). - In WordStarWordStarWordStar is a word processor application, published by MicroPro International, originally written for the CP/M operating system but later ported to DOS, that enjoyed a dominant market share during the early to mid-1980s. Although Seymour I...
, it was ++. - In emacsEmacsEmacs is a class of text editors, usually characterized by their extensibility. GNU Emacs has over 1,000 commands. It also allows the user to combine these commands into macros to automate work.Development began in the mid-1970s and continues actively...
, a file was opened with + followed by + (for find-file).
Some programs used to cancel an action. while some used it to complete one; WordPerfect used it to repeat a character. Some programs used to go to the end of a line, while some used it to complete filling in a form. was often help, but in WordPerfect, help was on instead. sometimes toggled between overtype and inserting characters, but some programs used it for "paste".
Thus, every program had to be learned individually and its complete user interface memorized. It was a sign of expertise to have learned the UIs of dozens of applications, since a novice user facing a new program would find their existing knowledge of a similar application absolutely no use whatsoever.
The detailed specification drew some of its inspiration from Apple Computer
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
's lavishly detailed human interface guidelines
Human Interface Guidelines
Human interface guidelines are software development documents which offer application developers a set of recommendations. Their aim is to improve the experience for the users by making application interfaces more intuitive, learnable, and consistent. Most guides limit themselves to defining a...
. The Apple HIG is a detailed book specifying exactly how software for the Apple Macintosh computer should look and function. When it was first written, the Mac was new, and Graphical user interface
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...
(GUI) software was a novelty, so Apple took great pains to ensure that programs would conform to a single shared look and feel. CUA had a similar aim, but it faced the more difficult task of trying to impose this retroactively on an existing, thriving but chaotic industry, with the much more ambitious goal of unifying all UI— from personal computers to minicomputers to mainframes; and supporting both character and GUI modes; and both batch and interactive designs. By comparison, the Apple HIG only supported Interactive GUI on a single personal computer.
Description
The CUA contains standards for the operation of elements such as dialog boxDialog box
In a graphical user interface of computers, a dialog box is a type of window used to enable reciprocal communication or "dialog" between a computer and its user. It may communicate information to the user, prompt the user for a response, or both...
es, menu
Menu (computing)
In computing and telecommunications, a menu is a list of commands presented to an operator by a computer or communications system. A menu is used in contrast to a command-line interface, where instructions to the computer are given in the form of commands .Choices given from a menu may be selected...
s and keyboard shortcut
Keyboard shortcut
In computing, a keyboard shortcut is a finite set of one or more keys that invoke a software or operating system operation when triggered by the user. A meaning of term "keyboard shortcut" can vary depending on software manufacturer...
s that have become so influential that they are implemented today by many programmers who have never read the CUA.
Some of these standards can be seen in the operation of Windows itself and DOS-based applications like the MS-DOS 5 full-screen text editor
Text editor
A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....
edit.com. CUA hallmarks include:
- All operations could be done with either the mouse or the keyboardComputer keyboardIn computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...
; - Menus are activated/deactivated with the key;
- Menus are opened by pressing the key plus the underlined letter of the menu name;
- Menu commands that require parameters to proceed are suffixed with an ellipsisEllipsisEllipsis is a series of marks that usually indicate an intentional omission of a word, sentence or whole section from the original text being quoted. An ellipsis can also be used to indicate an unfinished thought or, at the end of a sentence, a trailing off into silence...
("…"); - Options are requested using secondary windows (often called dialog boxes);
- Options are divided into sections using notebook tabs;
- Navigation within fields in dialog boxes is by cursor key; navigation between fields is by pressing the key; + moves backwards;
- Dialog boxes have a 'Cancel' button, activated by pressing the key, which discards changes, and an 'OK' button, activated by pressing , which accepts changes;
- Applications have online help accessed by a Help menu, which is the last option on the menu bar; context sensitive help can be summoned by ;
- The first menu is to be called 'File' and contains operations for handling files (new, open, save, save as) as well as quitting the program; the next menu 'Edit' has commands for undo, redo, cut, copy, delete, paste commands;
- The Cut command is +; Copy is +; Paste is +;
- The size of a window can be changed by dragging one of the 8 segments of the border.
CUA not only covered DOS applications, but was also the basis for the Windows Consistent User Interface standard (CUI), as well as that for OS/2 applications — both text-mode and the Presentation Manager
Presentation Manager
Presentation Manager is the graphical user interface that IBM and Microsoft introduced in version 1.1 of their operating system OS/2 in late 1988.-History:...
GUI — and IBM mainframes which conformed to the Systems Application Architecture
Systems Application Architecture
Systems Application Architecture is a set of standards for computer software, developed by IBM in the 1980s and implemented in IBM operating systems including MVS, OS/400 and OS/2...
.
CUA was more than just an attempt to rationalise DOS applications — it was part of a larger scheme to bring together, rationalise and harmonise the overall functions of software and hardware across IBM's entire computing range from microcomputers to mainframes. This is perhaps partly why it was not completely successful.
The third edition of CUA took a radical departure from the first two by introducing the object-oriented workplace
Workplace Shell
The Workplace Shell is a object-oriented desktop shell produced by IBM's Boca Raton development lab for OS/2 2.0. It is based on Common User Access and made a radical shift away from the Program Manager type interface that earlier versions of OS/2 shared with Windows 3.x or the...
. This changed the emphasis of the user's interactions to be the data (documents, pictures, and so on) that the user worked on. The emphasis on applications was removed with the intention of making the computer easier to use by matching users' expectations that they would work on documents using programs (rather than operating programs to work on documents). (See also object-oriented user interface
Object-oriented user interface
In computing an object-oriented user interface is a type of user interface based on an object-oriented programming metaphor. In an OOUI, the user interacts explicitly with objects that represent entities in the domain that the application is concerned with. Many vector drawing applications, for...
.)
Influence
CUA strongly influenced the early Microsoft WindowsMicrosoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
operating system during the period of joint IBM and Microsoft cooperation on OS/2 Presentation Manager. But later releases of IBM's CUA documents were not used for Microsoft products, and so CUA became less significant in the Windows environment. For instance, the Start menu
Start menu
The Start Menu and Start Button are user interface elements used in the later versions of the Microsoft Windows operating systems and in some X window managers...
was introduced, which removed the emphasis on an object-oriented desktop. Most of the standard keystrokes and basic GUI widgets specified by the CUA remain a feature of Windows, but few users are aware of them.
CUA has never had significant impact on Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
terminal (character-mode) applications. However, all major Unix GUI environments/toolkits (whether or not based on the X Window System
X Window System
The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...
) have featured varying levels of CUA compatibility, with Motif/CDE
Common Desktop Environment
The Common Desktop Environment is a desktop environment for Unix and OpenVMS, based on the Motif widget toolkit.- Corporate history :...
explicitly featuring it as a design goal. The current major environments, GNOME
GNOME
GNOME is a desktop environment and graphical user interface that runs on top of a computer operating system. It is composed entirely of free and open source software...
and KDE
KDE
KDE is an international free software community producing an integrated set of cross-platform applications designed to run on Linux, FreeBSD, Microsoft Windows, Solaris and Mac OS X systems...
, also feature extensive CUA compatibility. The subset of CUA implemented in Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
or OSF/Motif is generally considered a de-facto standard to be followed by any new Unix GUI environment.