Cache Manager

[wwshen@eecs.umich.edu]

> No, many programs will get confused if files are changed while they
> are reading (or executing them) so the local programs will not see the
> modifications before the file is closed.

   So you mean that AFS is "last close wins". The first client opens
a file and the 2nd client opens it later and closes it before the 1st
closes. Then after the 1st client closes the final version of the file
is decided by the 1st client. So why do we need the callback? I am still
not clear about this. 

   I am trying to reading your source code. As far as I know about AFS,
the file open system call, issued by the application program, is
intercepted by a small "hook" installed in the workstation's kernel.
The user's program is suspended and the intercepted request is divereted
to the Cache Manager, implemented as a user-level process on the
workstation. The cache manager then forwards the file request to a file
server, receives the file, stores it on the local disk, .....  So could
you tell me which files and functions in arald implement the beginning
function of the cache manager? I think your detailed explanation will
help me to understand how you do it?

   THank you very much again for your help.
best,
wuwei