Here. Brad Abrams describes how the Whidbey .NET Framework adds support for tracking unmanaged memory and limited resources of a non-memory nature. The former is handled by informing the GC of added "pressure" associated with unmanaged memory and the latter by exposing the private HandleCollector class that .NET 1.x has used for a while now. It's not reference counting, but it'll do for a start... : )
