Re: Hierarchical tag structure in SetFS

On Fri, Mar 02, 2007 at 01:51:51PM +0000, Tuomo Valkonen wrote:
> On 2007-03-02, Sam Mason <[email protected]> wrote:
> > And how do you ensure that every program can interact with every file?
> 
> Mounting the naming system somewhere in the global namespace?
> Or maybe URL-style stuff, if we didn't have to stick to the unix
> namespace (which we would): setfs://foo/bar/

URLs are only useful for opening a file when you know the name.  I
wouldn't like to type complete filenames (with all path elements)
each time I wanted to open a file.  Things like tab completion and
working directory only really work when you have something with similar
semantics to a hierarchical file system and can afford to expose the
interface.

> > Capability Systems 
> 
> Of course, supposing all files are not in a global namespace, 
> a private namespace is a capability system: to give a program 
> an access to a file, the program giving the capability would 
> map it in the requesting program's namespace and naming system
> (at a requested location). 

If you have to work with namespaces then this is about all you can do.
Inside a real capability system you would just ask something (the GUI
normally) to interact with the user and give you back a capability
(similar semantics to a "reference" in programming terms) to the file(s)
the user selected.

> But I'm not to keen on namespaces private to processes...

Capability systems generally don't imply private namespaces, it's just
the only obvious way to implement this sort of thing under Linux.


   Sam