[E-Lang] Remote Object E Question

[Karp, Alan]

MarkM wrote:
> 
> Alan, you may be amused that the main modification to the 
> CapTP needed to 
> support this is the option not to shorten 3-vat Granovetter 
> introductions, 
> much as E-Speak2.2 did not.  Were these shortened, they would 
> not be revoked 
> when the original vat was killed.  Precisely my argument for 
> shortening -- 
> that the capabilities should not be vulnerable to the death of the 
> introducing vat -- is here the reason not to shorten.  Of course, for 
> grant-matching reasons, unshortened capabilities cannot 
> present the sameness 
> identity of the object they forward to.  Therefore, they will 
> probably 
> remain unresolved, which is a bit weird but correct.  (Unshortened 
> E-Speak2.2 could not support grant matching for the same reasons.)
>

Once again I got the right answer for the wrong reason.  We did not default
shortening because we thought we had developed a broker pattern.  By not
introducing Bob to Carol, Alice's brokering business is protected.  An added
advantage is that Bob and Carol have no need to establish a trust
relationship with each other.

As far as grant matching goes, we proposed providing an askBob() interface
(different Bob; the reason for the name is worth a beer).  Given two object
references, invoke each one's askBob() method.  When the first message
reaches its object, the object responds with "Got the first message".  When
the second gets there, the object responds with "Got the second message".
If the sender gets two first messages, the two references refer to different
objects.  There are a variety of security and network delay issues that need
addressing, but I don't believe they are insurmountable.

_________________________
Alan Karp
Principal Scientist
Decision Technology Department
Hewlett-Packard Laboratories MS 1U-3
1501 Page Mill Road
Palo Alto, CA 94304
(650) 857-3967, fax (650) 857-6278
https://ecardfile.com/id/Alan_Karp
http://www.hpl.hp.com/personal/Alan_Karp/