_______________
           |               |   _______________
           | xterm         |  |               |
           |     __________|  | Xserver       |
           |    |          |  |               |
 _______   |    | Xtoolkit |  |      _________|
|       |  |    |----------|  |     |         |
| a.out |  |    | Xlib     |  |     | xdriver |
|_______|  |____|__________|  |_____|_________|
|       |  |               |  |               |
| libc  |  | libc          |  | libc          |
|_______|  |_______________|  |_______________|     USER
    |        |         |         |      |  |
____|________|_________|_________|______|__|_______
    |        |         |         |      |  |
 ___|________|___   ___|_________|___   |  |
|                | |                 |  | [drv?]
|  pty           | |  IPC(socket)    |  |  |
|________________| |_________________|[drv]|
                                        |  |        KERN
________________________________________|__|_______
                              __________|  |
                        _____|_____     ___|___
                       |           |   |       |
                       | KBD/Mouse |   | Video |
                       |___________|   |_______|    HW
___________________________________________________

koie