&gt; Security wouldn&#x27;t be possible without this. You can also think of cgroups&#x2F;lxc&#x2F;docker as a direct extension of this.<p>I maybe didn&#x27;t express myself clearly enough. The unix user system wasn&#x27;t designed for the program isolation it is used for today, but for multi-user systems.
The security model was to protect the system from users and users from each other.<p>Cgroups are certainly a move into the correct direction, because it&#x27;s based on the assumption that programs are evil (either by design, or because they get exploited).
When you correctly sandbox programs you won&#x27;t need to run them as a different user anymore.