"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."
Web site: http://os2.kiev.ua/en/sses.php
Support forum: http://os2.kiev.ua/en/forum.list.php?f=5
Download: ftp://ftp.os2.kiev.ua/sses/sses-alpha-0.3.1.zip
>From Changelog:
0.3.1
Fixed number of registered users overflow bug in
DosUserUnsetEffectiveUser caused fails of DosUserRegister after some time.
Source: OS2VOICE