It may not be that Mandriva defaults to that, it may be result of my own bull-in-china-shop foolery.
If I go into /etc/pwd (I'll check for exact expression!), and found anything resembling what you found, I doubt it would be more useful than than reading coffee grounds, but will look anyway of course, and check settings as you suggest.
I got lost for a while by playing with desktops, Xfce,Ice,and uh-oh, I should have guessed by the name, Failsafe. got stranded in there with only one command at my cerebral disposal, 'ls'.
After some hours tried 'help', and one word of many offered, namely 'logout', saved me.
ANYWAY, it's with delight that I report that the Xfce desktop is just what this ancient Dell laptop 512 RAM needed for navigational speed. Well worth it.