Plan 9 From Bell Labs - Combining The Design Concepts

Combining The Design Concepts

Though interesting on their own, the design concepts of Plan 9 were supposed to be most useful when combined together. For example, to implement a network address translation (NAT) server, a union directory can be created, overlaying the router's /net directory tree with its own /net. Similarly, a virtual private network (VPN) can be implemented by overlaying in a union directory a /net hierarchy from a remote gateway, using secured 9P over the public Internet. A union directory with the /net hierarchy and filters can be used to sandbox an untrusted application or to implement a firewall. In the same manner, a distributed computing network can be composed with a union directory of /proc hierarchies from remote hosts, which allows interacting with them as if they are local.

When used together, these features allow for assembling a complex distributed computing environment by reusing the existing hierarchical name system.