(Many open questions below are a bit arcane and may not be relevant to IV or projects.)
I feel “managed” means “automatically-released”. In that case, most dotnet Objects qualify as managed “Resources”. Any time you need Dispose() in your CLASS, that’s a telltale sign of unmanaged resources.
“Resource” is a rather abstract term, best understood by example. In my mind, a resource is some runtime object(s) needed by our App, something constructed and configured. Like a natural resource it is scarce, shared and rationed. Like a library book, there’s usually an acquisition “protocol”, and a return protocol.
 As a crude example, what’s a city and what’s not a city? Best learn by example.
http://stackoverflow.com/questions/13786570/determine-managed-vs-unmanaged-resources has some interesting comments.
–Unmanaged resource and … IntPtr + handle ?
What’s an IntPtr? Basically a struct that represents a native void pointer (or a native handle) —
http://stackoverflow.com/questions/1148177/just-what-is-an-intptr-exactly Many unmanaged “resources” are accessed via IntPtr.
–Unmanaged resource and unsafe code?
–Unmanaged resoruce and p/invoke?
–Unmanaged resource and … win32 + COM?
–some managed resources
filestream is a MR. It contains a native file handle, which is UR. It’s IntPtr, but not a integer-based file descriptor as in C/python. See MSDN.
A socket object is a MR. It contains a socket handle, which is UR and IntPtr
A DB connection is probably UR.