http://hobbes.nmsu.edu/cgi-bin/h-search?key=sses-alpha-0.2.5.zip
Web site: http://os2.kiev.ua/en/sses.php
"Security/2 is a multi-user system for OS/2. It provides controlled access to files, drives, drivers and other OS/2 stuff, based on access control list for each user. Security/2 has modular structure and can be easily (i hope ;)) extended and provides a API for developers to enable their applications be multi-user."