[cap-talk] origin of the power box

[Neal H. Walfield]

What is the origin of the power box idea?  Mark Seaborn states on
http://plash.beasts.org/ that 

  The powerbox concept appears to have first been proposed by Ka-Ping
  Yee and Miriam Walker in Interaction Design for End User Security
  (December 2000).

I find it amazing that this idea was suggested so recently.  How did
earlier capability systems handle run-time access delegation?

Thanks,
Neal