K 10 svn:author V 7 rwatson K 8 svn:date V 27 2007-05-11T12:10:45.000000Z K 7 svn:log V 187 Clarify and update quite a few comments to reflect locking optimizations, the addition of unpcb refcounts, and bug fixes. Some of these fixes are appropriate for MFC. MFC after: 3 days END