Lightweight processes Mail News work xinu

[Rene' Seindal]

What is the definition of  ``lightweight processes'' ?

I know the NeWS system contains something they call lightweight
processes, where they have a process per window, passing messages
forth and back, and I have seen some notes about SunOS4.0, where the
same term was used.

The background for my asking is that I am currently working on getting
Xinu to run in a Unix process.  It is great fun.  My curiosity comes
from the SunOS4.0 note, where the user interface to these lightweight
processes was sketched, and it's apparent functionality had a striking
similarity to Xinu.  (I am not accusing anybody of anything!)

Any information would be appreciated. 

thanks

Rene' Seindal, DIKU, U. of Copenhagen, Denmark. (seindal at diku.dk)