A couple of things I was wondering about your DDE - have you made any attempt at getting other small OS projects to make use of it too, so as to spread maintenance and testing work? And have you tried getting changes into the Linux kernel to make drivers work more easily with your DDE? I know that the Linux people have traditionally been rather averse to the idea of sharing driver code with other OSes, but perhaps they would not mind as long as they are the upstream and the changes didn't adversely affect the Linux kernel (it would provide additional testing of their kernel driver code too).