Re: tlug: CODA distributed filesystem

["Manuel M. T. Chakravarty" <chak@example.com>]

Darren Cook <darren@example.com> wrote,

> >The client keeps a cache of files locally, and files in cache are
> >accessible even if the network abruptly cuts out (or you yank the
> >cable on your laptop and go home).  You can set priorities for
> 
> I read the overview (nice pictures) in the site whose URL you gave a couple
> a couple of days ago. The thing I wasn't clear on was what happens when two
> people are using the same file. My understanding was that this was allowed,
> and when they both save their changes back it will intelligently combine
> them if it can, otherwise human interaction is required.
> 
> That sounds a bit dangerous. I'd have thought if it was in one machines
> cache (and not flagged as read-only) then everyone else should be refused
> access to it. But then either you get problems with people hoarding files,
> or you force the cache to be emptied regularly and then the cache becomes
> less useful.

I don't that this is really a problem in a typical Linux
file system, where each user works in his or her home
directory (where other users typically don't have access
right).  It gets critical only when changing files belonging 
to root, which is probably not very clever while being
disconnected from the machine that your are just
reconfiguring.  Or when one user changes something say on a
laptop, then without connecting the laptop changes the same
file on a desktop machine, and finally connects the laptop.
But in this case, it is one person who makes both changes
and has to face the consequences.

Manuel
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