Poul-Henning Kamp's `chroot_jail` implementation for RCN

Poul-Henning Kamp, addressing a critical security need for RCN, developed an initial, more robust form of process and network isolation beyond simple `chroot`, laying the foundational concept for Jails.

Significance

This custom solution demonstrated the practical feasibility and immense value of OS-level virtualization, directly inspiring the kernel-level 'jail' system call.