The device space is the coordinate space in which a picture is drawn before it appears in a display screen window or on the printer or plotter.
Device space is defined in device-specific units. Depending on the page unit used, device-coordinate units can be pels, increments of an inch, increments of a meter, or arbitrary. For example, if the page unit is pels, the device-coordinate unit is pels; if the page units are arbitrary, the device-coordinate units are arbitrary.