[cap-talk] Objects and Facets

[Ian G]

Mark S. Miller wrote:


> The object-capability model is explained starting in section 9.1 p64. There we 
> state:
> 
> * An object is either a primitive or an instance. Later, we explain three
>    kinds of primitives: data, devices, and loaders. Data is immutable.
> * An instance is a combination of code and state. We say it is an instance of
>    the behavior described by its code. For example, in an operating system
>    context, we say a process is an instance of its program. In a lexically
>    scoped lambda language, a closure is an instance of its lambda expression.
> * A reference provides access to an object, indivisibly combining designation
>    of the object, the permission to access it, and the means to access it.
> * A capability is a reference to non-data.


Reverse-engineering the above, is it fair to suggest:

* Non-data is objects of the forms:  devices, loaders, instances?

Or

* Non-data is objects that are non-immutable?

Still searching for the difference between the capability and the
object/reference here;  it seems that you are suggesting that
capabilities are in the broad sense a limited subset of objects
(must include some sense of dynamic state).

iang

PS: or, as David H suggests, "... references to such objects."