[2] The /sys filesystem on Linux complements /proc, by providing a lot of (non-process related) detailed information about the in-kernel status to userspace.
On the Plan 9 from Bell Labs operating system family, the concept of 9P synthetic filesystem is used as a generic IPC method.
Plan 9 drives this concept expansively: most operating system services, e.g. hardware access and networking stack are presented as fileservers.
[citation needed] Several protocols have been implemented to provide direct access to in-chip devices, but they tend to be proprietary, complex and hard to handle.
The major benefit is that 9P is very simple and so quite easy to implement in hardware and can be easily used and over virtually any kind of network (from a serial link up to the internet).
For example, complex remote procedure calls with many parameters tend to be hard to map to filesystem schemes,[citation needed] and may require application redesign.