Re: Need for sensory capabilities Mark S. Miller (markm@caplet.com)
Mon, 21 Dec 1998 11:33:30 -0800

At 05:40 AM 12/21/98 , shapj@us.ibm.com wrote:
>... In the absence of sensory capabilities, it is NOT possible to decide
>endogenously whether a given subsystem is confined. ...
>
>There may, however, be other possible solutions that achieve the same
>effect.

[?] Is "transitively immutable" an adequate substitute?

E does have a "transitively immutable" property which can be reliably declared and checked. Transitive immutability is a stronger constraint than sensory, and provides for both confinement and durability. This is E's candidate for such an "other possible solution".

However, by being a stronger constraint, it forbids some of the arrangements that "sensory" provides. It would be great to understand whether this loss of flexibility will create serious problems for us, before finding out the hard way.