Storing GUIDs in linux [filesystems]

[Sankar P]

Hi,

http://en.wikipedia.org/wiki/Globally_unique_identifier is one way to
uniquely identify users. It is used by Windows and Active Directory
too. The size of a GUID is 128 bits.

I want to store the GUID of an user on my experimental filesystem.

The size of the "uid" in UNIX is just 16 bits. So what is the way used
by the Linux [filesystems] to store the GUID in linux to uniquely
identify an user ?

Were there any proposals in the past, to increase the size of the unix
uid to match that of a GUID ?

-- 
Sankar P
http://psankar.blogspot.com