The information display page is an area, 40 characters wide by 33 lines deep, that contains the static information that you want to display on the screen.
The width of the virtual display is handled as two columns, each of 20 characters, unless a special bit (the wrap indicator) is set. In this condition the two columns are handled as a single 40 character column. The ADSI command statements enable the display of either or both of the columns on the screen, and tabbing between them. A number of formatting options (left or right adjust, center or indent) can be applied either to the individual columns, or to the 40 character lines if wrapping is requested.
The 33 lines can be divided into logical sections so that information for different scenarios can be held in memory at the same time. The user can scroll up and down a logical section of the virtual display without running into another section.