framiere
Basically by order of appearance you look for
* well know files, or registry keys
* patterns in a memory dump
* use a great hack called "the red pill" using the SIDT instruction
* vm specific hardwares
* specific instructions/capabilities
Example :
you make a remark without really thinking of it because of your professional habits (ex: you should be doing things that way, or going straight to limit-cases or counter-examples) that would made sense in a professional context, but that is not acceptable outside.
You would apologize saying "I am sorry, it is a déformation professionelle"
Look at http://blogs.azulsystems.com/cliff/2007/03/a_nonblocking_h.h... : an implementation of a non blocking hashmap without lock that scales beautifully on a bunch of cores without the need of their hardware (http://sourceforge.net/projects/high-scale-lib)
As per actor on the JVM open source projects are blooming around such as http://code.google.com/p/actorom/.
Alex Miller did a nice review here of the solutions out there: http://www.javaworld.com/javaworld/jw-03-2009/jw-03-actor-co...
Check http://blogs.azulsystems.com/cliff/ for really impressive work on jvm that works on 800+ cores ... oh yes, and you have constant time garbage collection.
It is a very useful approach to prevent regressions while working on legacy code.
Alberto Savoya (who is behind agitar) has a nice definition of legacy code : code that has no unit-test.