UIDs are cross session, IF (and only IF) the UIDVALIDITY is unchanged. And there ARE existing, compliant servers which will give a different UIDVALIDITY for every session (if the underlying message store is incapable of implementing UIDs).
However, this "cross-session" characteristic is much less than Mike seems to expect.
The fact that a UID is known to a session does not mean that it is known to another (even a simultaneous) session. There are many ways that a message can be known to one session but not another. UIDs only promise that a particular UID will not refer to two different messages.
In other words, UIDs are a means by which an application can synchronize itself in a session using data from another (typically chronologically earlier) session. Sessions do not synchronize on their own, although simultaneous sessions will tend towards synchronization over time.
> File state, while it can not be relied on to be correct the minute the > server responds to an ls for example, it can be relied on to be > consistent between sessions.
I just noticed this comment of Mike's. It's false, as anyone who has spent any non-trivial amount of time dealing with NFS can testify.
Sad, but true.
-- Mark --
http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate. Si vis pacem, para bellum.
