What is RCU, Fundamentally?

"One key attribute of RCU is the ability to safely scan data, even
though that data is being modified concurrently. To provide this
ability for concurrent insertion, RCU uses what can be thought of
as a publish-subscribe mechanism."

Does this not read like that once announced Microsoft Filesystem called
WinFS ? From the WinFS wikipedia penal records :

http://en.wikipedia.org/wiki/WinFS

"WinFS (short for Windows Future Storage)[1] is the code name for a
cancelled[2] data storage and management system project based on
relational databases, developed by Microsoft and first demonstrated
in 2003 as an advanced storage subsystem for the Microsoft Windows
operating system, ...
[ ... ]
WinFS includes a relational database for storage of information,
and allows any type of information to be stored in it, provided
there is a well defined schema for the type."

It's funny to see IBM, amongst others, explain the 'dirty' details about 'RCU'
here on LWN.

Robert
--
Robert M. Stockmann - RHCE
Network Engineer - UNIX/Linux Specialist
crashrecovery.org stock@stokkie.net