[cap-talk] A Taxonomy of Current Object-Cap Systems

Charles Landau clandau at macslab.com
Thu Mar 5 17:15:55 EST 2009

Mark Seaborn wrote:
> Are you only considering pure capability systems?  Unix file
> descriptors, and in particular Unix domain sockets could go on the
> list.  The comparison would be useful, considering that sockets are
> connection-based (unlike EROS/CapROS/Coyotos and typical
> language-based objects) and often not message-based.

I don't see the distinction. EROS/CapROS/Coyotos capabilities can be to 
objects that represent a session or connection.

Rob Meijer wrote:
> In my view UNIX domain sockets when used for IPC have all the properties
> needed to be considered object capabilities.  IMHO to turn a multi process
> application using UNIX domain sockets for IPC into an object capability
> system, all what is needed is to take away everything that could be
> considered to be ambient authority.

AFAIK it's not possible to send a socket through a pipe. That would 
either disqualify them, or call for another taxon: whether capabilities 
can be sent in messages.

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