Randy thanks. There are some diaries but they are open for everybody or open for everybody if logged-in. Not for a certain user.
I agree that I have to start a little project to rewrite a plugin.
It would not be a great project:
a logged in user can sequential add text per date/time
only the user with the right userid can do this
in his own admin environment he can look into his diary top-down
add a new records + automatically date/time registration.
thats it.