Softupdates: any internals doc.?

[Shamim Mohamed <shamim_(_at_)_jantar_(_dot_)_languid_(_dot_)_org>]

I want to know more about exactly what softupdates does; can someone
recommend a decent document? I have a graduate-level CS background and
am familiar with filesystem design etc. so I'm looking for something
technical.  I guess I could just go read the source, but that might
take a little longer than I'd like, I don't know FFS internals.  (I
don't have access to CS journals any more, I'd like something on the
web.)

Thanks!

-s