Generally the kernel debugger communicates over a serial communications link with a terminal emulator program running on another machine. This allows a user to debug a problem by issuing kernel debugger commands in the emulator program and seeing the results displayed on the debug console.
To automate the debugging process, or to provide a high-level language debugging environment, this interaction with the kernel debugger could instead be handled by a program running on the other machine. This debug engine would interact with the user, convert the user's debugging request to a series of kernel debugger commands, issue them, and then present the response from the kernel debugger back to the user in a user-friendly format.
Communications between the debug engine and the kernel debugger can proceed in one of two modes:
raw (dumb TTY) mode