The Presentation Manager user interface model facilitates an intuitive user interface. While people typically approach their work tasks from a "problem-domain" viewpoint, computers tend to adopt an "operator/operand" approach that is inherently alien to the end user. Traditionally, the required translation between approaches has been left to the user, with applications and their user interfaces written to conform to the computer's viewpoint rather than that of the user. This approach has often led to users having difficulty relating to the technology, with consequently greater amounts of time and money spent in user training.
In recent times, a growing school of thought has emerged which contends that, with the increasing power of computer systems and particularly with the advent of powerful programmable workstations, the responsibility for this interface translation should lie primarily with the application or the computer system rather than with the user. In order to achieve this, user interfaces must be redesigned in order to operate in an object-action, event-driven manner which corresponds with the users' problem domain viewpoint.
Presentation Manager implements such a user interface, and Presentation Manager applications may thus be designed and implemented in such a way as to provide improved user-friendliness and encourage learning by exploration. The details of the Presentation Manager user interface are described in OS/2 Version 2.0 - Volume 3: Presentation Manager and Workplace Shell.
Presentation Manager also facilitates consistency between applications by handling the interface between user and application at a system level, providing a number of standard constructs which may be exploited by applications. Since these constructs typically appear and behave in the same way regardless of the application under which they are implemented, a user need learn only one set of user interface guidelines to be able to interact with multiple applications. This consistency reduces confusion for users who work with multiple applications, and reduces the need for extensive application training.
The SAA CUA component provides guidelines for the use of these constructs to fulfill particular input/output requirements within an application, such that a level of consistency is achieved not only in the behaviour of the constructs themselves, but also in their relationship to one another and thus in the behaviour of the application as a whole. These guidelines are documented in the IBM Systems Application Architecture CUA Advanced Guide to User Interface Design.