From: "Karp, Alan" <>
Date: Wed, 4 Dec 2002 14:51:16 -0800
Subject: RE: [e-lang] "Capability Myths Demolished" (was: Software securi ty workshop)

Tyler Close wrote:
> Given this mechanism, you can implement all the functionality of
> the Granovetter diagram.  How can you draw a line between the
> Dennis and Van Horn system and E?

As described in Dennis and van Horn, a capability contains an identifier for a segment (resource) and a set of rights.  A c-list is a set of handles to these capabilities.  The permissions are explicitly listed in the capability and are interpreted on access to the resource.  My understanding of an E-capability is that it is an identifier to a facet of a resource, identical to an object handle.  The permissions are implicit in the facet being identified.  No interpetation of rights is needed; either the facet has the method, or it doesn't.  That's why in my paper I list E-capabilities as different from what I call traditional capabilities. tyler   

Alan Karp
Principal Scientist
Decision Technology Department
Hewlett-Packard Laboratories MS 1141
1501 Page Mill Road
Palo Alto, CA 94304
(650) 857-3967, fax (650) 857-6278
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