hierarchy_stoplist & always_direct

Having been reconfiguring for electronic journals & datasets I have a query
about the difference between the 2 directives:

hierarchy_stoplist:

Stops Squid querying other caches for - is this just do not send ICP?
I assume from the patch Duane sent me also meant to stop use of cache_digest
as well.
How does this interact with never_direct?
How does this interact with parents?

always_direct:

Always send requests to origin server - ie if not locally cached, go direct.

(There is the no_cache directive to stop things being cached locally).

I can not see the difference in effect between hierachy_stoplist and
always_direct

BTW the problem I suffer with request satisfied by cache digest hit despite
being in hierarchy_stoplist also applied to always_direct

-- 
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| Peter Polkinghorne, Computer Centre, Brunel University, Uxbridge, UB8 3PH,|
| Peter.Polkinghorne@brunel.ac.uk   +44 1895 274000 x2561       UK          |
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