DIfference between slave threads and worker processes

Reference

http://code.kx.com/wiki/Cookbook/MultithreadedInputMode

http://code.kx.com/wiki/Reference/peach

Question:

Is the first one slave threads and 2nd one worker threads ?

q p -5000 -s 4 

q p -5000 s 4 / .z.pd will give the peach handle with `u# attribute