Interface Model s Programmer Reaction s Asynchronous Multiple Processes Implementation s Frame window Process window Source Text window s current expression s current window s data structure s multiple windows g pop-up menus source line s source text s src text subject process s user interface I ps c /proc c debugger g C C++ interactive debugger g expressions s spy expressions s 5620 breakpoint core dump Signals S RawMemory S Assembler S Journal S stop S kill S Globals S object-oriented programming ~killian run S src text S format S $ s