Robert King wrote in a message to Mike Bilow:

 RK> I could be mistaken but, I have been told by Developer
 RK> Support that the HPFS driver IS 32 bit as of OS/2 version
 RK> 2.11. I haven't looked into the code but, it is much
 RK> snappier than it's 2.0/2.1 counterpart..

For HPFS or anything else, an IFS is a 16-bit DLL that runs at ring 0. 
While a 16-bit IFS (or PDD) may use 32-bit registers and 386 instructions,
it still must interface to the outside world using 16-bit conventions,
16:16 pointers, and so forth.

If you want to check this yourself, examine the HPFS.IFS file.  Under OS/2
2.11 or 3.0, you will find that it is an NE-format module, which only
supports 16-bit segments.
 
-- Mike


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