.NET Garbage Collection and Native Threads
Does this help?
"A GC won't stop threads that are notrunning managed code. Since thosethreads can't be touching the GC'sheap anyways, there's no need for theGC to coordinate with them."
"If a thread was in managed code butcalled out to native code, it willcontinue to run. It will be stopped ifit returns back to managed code."