Introduction to Process Concepts
The APPX process facility recognizes nine process types: menu, input, output, query, subroutine, update, job, status and inquiry. Each represents a specific kind of activity, and each is comprised of a subset of the structural components (PCFs, frames, and event points, for example) that were described in the previous chapter. However, while the structural components are essentially the same from type to type, the way these components are used to perform a required activity varies. For example, menu and inputprocesses use images toformat the screens that display to a user. Output processes, on the other hand, generally use images to format hard copy, such as a list or report. And subroutine processes do not display information to a user, so no images are required.
Because of such differences, there are a number of concepts that apply to one or more, but not all, process types in APPX. To continue the previous example, the way you position images on a frame has obvious significance to a menu, input, or output process, but no relevance at all to a subroutine. To carry the example even further, there are subtle differences between image positioning for input and output images, because the former display on the screen, while the latter generally print on hard copy. The material that follows discusses a number of these process-specific concepts in detail.
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