"For some time the filesystem in Linux was a fairly simple tree.
A process could chroot() itself as though the root of the
filesystem tree was a subdirectory of the system's filesystem root.
At any node in the tree, a filesystem could be overlaid from a new
"In 2000, Al Viro introduced bind mounts and filesystem
namespaces for Linux:
"A bind mount allows any file or directory to be accessible
from any other location.
"Filesystem namespaces are completely separate filesystem trees
associated with different processes..."