[OpenAFS] afs vs nfs

[Jim Rees]

  Read carefully.  I attended an NFSv4 presentation at a technical conference, 
  and found out that some of the NFSv4 features were added specifically to 
  compete with afs; however, the implementation is in the spec as "optional", 
  and, in fact, none of the existing NFSv4 implementations have them.

That's one way to look at it.  Another is that when you are designing a file
system, or any system, it's a good idea to look at what has worked or not
worked in the past, and learn from others' mistakes.  NFSv4 takes
inspiration from many other systems, not just afs.

You are probably thinking of delegations, which allow clients to cache data
without having to check back with the file server whenever they want to use
the data.  As far as I know none of the existing clients do any client
caching of data.