Alan, these posts are always so stimulating.  Could
you tell me a little about abstact algebras and how
you relate them to computers sending messages to other
computers?  Is it related to defining languages, in
some way?

you also wrote:

> An interesting consequence of this structure was
> that protection was 
> complete in ST-72, and all messages could be
> serialized if the object 
> wanted (we did not bother with this because we were
> working on 
> different kinds of problems -- but Hewitt thought
> about it a lot).

Could you say a little more about why protection was
ensured?  Also, I like the implications of serializing
all msgs.  How did this work in these systems?

thanks!
journeyman rob