[cap-talk] Concening entry "ambient authority" in Wikipedia

[Charles Landau]

Marcus Brinkmann wrote:
> A close analysis will reveal that the situation is not so simple.  For
> example, the wikipedia page "Object-capability_model" cites Java global
> variables as a different way to access resources.  But in a capability system
> memory load/store instructions are *modeled* as messages to memory pages that
> are part of the processes page table, where the relevant capabilities are
> named implicitely through the architectures process model.  And in fact, the
> hardware's page table is just an optimized implementation of those
> capabilities

Are you saying that one can deny a Java program access to global 
variables by constructing an address space that lack the relevant memory 
page capabilities? I think not, otherwise they wouldn't be *global* 
variables.

To quote the Wikipedia page:

"An address can be obtained by: 1. creation: creating a new object ... 
2. receiving a message ... *all* computation is performed following the 
above rules."

If there are memory pages that aren't optional, they are received by 
some means other than the above. If that isn't clear, then the Wikipedia 
page needs to be updated.