[cap-talk] Capability analogies

[Karp, Alan H]

Jed wrote:
> 
> I like your metaphors Alan (I've used the valet parking example
> myself, though not with the ACL twist), but I'm not confident
> such metaphors will help much in getting people to understand
> capabilities.  In my experience (mostly with some 3k+ staff
> members at LLNL using the capabilities in the Elephant Storage
> system very successfully for some 25+ years) the capability concept
> itself as a simple reference to an object (in that case only
> directories and files) is simpler than any of the metaphors.
> 
Different audience.  I use these stories when talking to executives.
Talking about object references would be lost on them.
> 
> If, however, this particular 'ownership' privilege of
> being able to update the ACL is granted with every
> permission to access the object, then ACLs can serve
> much more like capabilities.    
 
HP Select Access allows this form of delegation, although its
administratively burdensome enough that it's not done for every granting
of a privilege.

________________________
Alan Karp
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Virus Safe Computing Initiative
Hewlett-Packard Laboratories
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