[E-Lang] Summary for Practical Programming

Mark S. Miller markm@caplet.com
Thu, 01 Feb 2001 15:01:47 -0800

At 02:44 PM Thursday 2/1/01, Bill Frantz wrote:
>Marc - Thanks for trying to summarize things.
>At 02:15 PM 2/1/01 -0700, Marc Stiegler wrote:
>>6. We all agree that POLA is an inherent characteristic in the nature of
>>capability systems, and to the various extents that each individual in this
>>discussion knows the actual behaviors of these implementations, POLA is a
>>part of both E and EROS as actual implementations.
>I am not sure about this one.  I think some of the early capability systems
>did not easily support POLA.  (Where is my copy of Levy.)  Certainly one
>could design a capability system where every call (by convention) passed a
>capability to the home directory.  I think a rewording is in order.

I hate to do this to you Alan, but I think you're our live representative of 
this family of systems.  From previous correspondence on the list, I have 
come to think of E-Speak2.2 firmly as a capability system.  (Certainly much 
more so than SPKI or E-Speak-3.)  However, I recall there was something like 
an implicit inheritance of vast amounts of authority from a parent to a 
child, analogous to Unix's fork() or exec().  I remember it struck the rest 
of us as a gross violation of POLA, you didn't disagree, but said it was 
necessary to avoid confusing your target audience.

Does any of this ring a bell?  Does it sound right?