This user interface (figure 
allows to attach
to / create the DD system. A child process dd_ctl is forked off
and its standard output is attached to the text widget.
A pull down menu allows to select commands, a text field
at the lower left corner accepts commands directly.
The interface is written in Tcl/TK 
.
The executable is $DD_BIN/dd_ui.
Figure:
The dd_ui user interface.