Video output functions begin writing in the window's buffer at the location specified by the virtual cursor. There is one virtual cursor for each window and its location is maintained in the window structure. The virtual cursor coordinates are relative to the window's buffer, not to the physical screen.
The virtual cursor position only holds the location where the next output to the window will be placed; it does not appear on the screen. Because each window has a separate virtual cursor, you can write to several different windows alternately without worrying about moving the virtual cursor location each time.
