Common User Access (CUA) is a standard for user interfaces to operating systems and computer programs. It was developed by IBM and first published in 1987 as part of their Systems Application Architecture. Used originally in the MVS/ESA, 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. Motivations and inspirations IBM wanted a standard way to interact with text-based user interface software, whether the screen was a dumb terminal connected to a mainframe or a PS/2 with VGA graphics. 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 DOS applications, which until then had independently implemented different user interfaces. For example, to open a file: In WordPerfect, the command to open a file was , . In Lotus 1-2-3, a file was opened with (to open the menus), (for File), (for Retrieve). In Microsoft Word, a file was opened with (to open the menus), (for Transfer), (for Load). In WordStar, (to get to the Opening Menu), followed by . In emacs, a file is opened with + followed by + (for find-file). In vi, use to allow commands, then to open the file browser. was often the help key (such as Volkswriter (1982)), but in WordPerfect, help was on instead. 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. 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 memorised. 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 either of no use or actively a hindrance to understanding as learned behavior might need to be unlearned for the new application. The detailed CUA specification, published in December 1987, is 328 pages long. It has similarities to Apple Computer's detailed human interface guidelines (139 pages). The Apple HIG is a detailed book specifying how