What does one mean by instrumentation when one talks in the context of
software development best practices?

<QUOTE
src="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_vstechart/html/AOPArticle.asp">
Contrary to popular belief, AOP can be useful to solve problems other
then Logging, Security, Instrumentation, and things of that nature.
</QUOTE>

ok! I think I got that from the google definitions. It is writing trace
information.