Split Capabilities: Making Capabilities Scale

[Karp, Alan]

> -----Original Message-----
> From: Mark S. Miller [mailto:markm@caplet.com]
> Sent: Thursday, July 20, 2000 3:22 PM
> To: Karp, Alan
> Cc: 'Jonathan S. Shapiro'; e-lang@eros-os.org
> Subject: RE: Split Capabilities: Making Capabilities Scale
> 
> 
> At 05:31 PM 7/11/00 , Karp, Alan wrote:
> >Ah, but non-selective revocation doesn't need preplanning in 
> e-speak Beta
> >2.2.  On talking to Mark, we realized that the methods are 
> similar, but we
> >took different approaches because of the relative costs of 
> the different
> >solutions.  In E, objects are cheaper than capabilities.  
> The exact opposite
> >is true in e-speak. 
> 
> In E I'm not sure what "objects are cheaper than 
> capabilities" would mean.  
> Objects and capabilities are 1-for-1.
> 

I thought that capabilities are handles for objects and each represents a
facet of an object.  An interposer is a running piece of code; a capability
is the handle used to access the interposer and the access rights of the
facet.  

My statement refers to the fact that the interposer need be nothing but two
lines of code to be a message forwarder, while a capability, if remote,
requires some cryptography.

> 
>          Cheers,
>          --MarkM
> 

_________________________
Alan Karp
Decision Technology Department
Hewlett-Packard Laboratories MS 1U-2
1501 Page Mill Road
Palo Alto, CA 94304
(650) 857-3967, fax (650) 857-6278