Side-effect free containers for E

[Jonathan S. Shapiro]

> >Curiously, KeyKOS and EROS are rife with subtypes that add authority (or,
> >equivalently, supertypes that subtract authority, ie, "thinning").

> I think I am very confused.  As far as I know, KeyKOS/EROS doesn't have
> types in a language sense.

Well, yes, it does. We just don't make them terribly explicit.  Also, it's
not clear that the type relationship has anything to do with sub/supertype.

There is a graph of the rights hierarchy somewhere in my dissertation.

The conversion of R/W foocap to R/O foocap is a pure reduction in strength.

The conversion of a node key to a domain key is a slight reduction in
strength, as the brand slot becomes inaccessable.

The creation of start/resume keys presents an interesting problem. Since a
node key cannot do this directly there is a curious question about the type
lattice that I need to think about at some point.

Weak (sensory) capabilities don't seem to lend themselves to a static type
characterization at all.

shap