11.3. User and Device Space   

PostScript operates on a plane which is described in terms of the usual mathematical x and y axes. This plane is referred to as user space, because that is where the user describes, by a series of PostSript commands, the text and graphics to be printed. .pp Device space is dependent upon the internal coordinate system employed by each type of PostScript output device to address the points on a page. This space will differ from device to device. ( A PostScript Cookbook, Barry Thomas, Macmillan, 1988)