From FBSD_tips

DRAFT - INCOMPLETE

[edit] Rationale

As easy to set up and use and as powerful as jail is, it has a forgotten little brother : chroot. Many applications offer chroot capabilities from with the exe. But whereas with jail, the system takes care of providing the devfs, with a chrooting application you are on your own to make sure the app has access to the devices it needs (e.g. nullfs). This will detail a simple case for providing that.