Listing files with ls causes a core dump
From: Julianne F. Haugh
Scenario: a directory that is shared by N users (N >= 200).
Run 'ls -l' in that directory. It goes for a while, then
It only occurs when the usernames are displayed (almost every file is
owned by a different person). The -g and -n options work fine; only -l
and -o (which shows owner and not group) cause it.
I believe that this problem was corrected by U407548. If you have that
many users that you are having core dump problems (it took over 200),
you might also want to look into getting the PTF that fixes IX31403.
That APAR deals with large numbers of accounts and performance problems
associated with looking them up.