From a previous blog entry :-
“… I noticed that the slave trace files are appearing in user_dump_dest. This is with 9.2.0.1.0 on Windows XP Home. I’m using 9.2 because I want to see the discrete SQL statements that the slaves are processing.
So, just an interesting anomaly from what I’ve seen previously. I’ll check it out on other versions / OS in future.“
Well, I’ve just tried it on 10.1.0.4 on XP at home and the px slave trace files are appearing in background_dump_dest, as usual.