env – environment variables
bind #e /env
device serves a one-level directory containing files with arbitrary names
The intention is that the file name is the name of an
and the content is the variable’s current value.
system call creates a new process, both the parent and the
child continue to see exactly the same files in the
device: changes made in either process can be noticed by the other.
In contrast, an
system call with the
bit set (see
causes a split: initially both process groups see the
same environment files, but any changes made in one process group
cannot be noticed by the other.
splits and then clears the environment.
The special global environment
contains kernel configuration variables,
such as those set in
All processes see the same
its contents are writable only by the host owner.
[XXX actually everything is world writable; that’s a mistake.]
A write starting at an offset after the current extent of a file
yields an error instead of zero filling.