XP - no dice to my knowledge.  no 7303h support, only 36h support.  7303h gives the old dos 1.0 "I'm going to pretend I'm not here" method.

From: Eric Auer <e.auer@jpberlin.de>
To: Walt Nagel <wrn71@yahoo.com>
Cc: jmichae3@yahoo.com
Sent: Mon, February 21, 2011 1:35:45 PM
Subject: Re: [Freedos-devel] documentation for FreeDOS filesystem or other programming functions/interfaces?

Hi Walt, Jim,

as Walt is probably not Leland, we are missing feedback from him ;-)

Regarding the program by Walt: How does it get correct information
from Win2000 / WinXP if those pretend to not support FAT32 calls and
just pretend that you always have 1 GB free according to FAT12/FAT16?

Regards, Eric

> I wrote a similar program to freetest (less a critical error handler;
> it will abort if an invalid drive number is entered). Keep in mind
> that the W2k/XP command line thinks of itself as DOS 5.0. Int 21-73xx
> is going to return an "unimplemented" value. Probably because my
> systems are running an NTFS on large drives, int 21-36 seems to
> always return 512 byte sectors, 127 sectors/cluster and 15,747
> sectors: this works out to about 1 GB free space. FreeDOS 1.0
> returned DOS 7.10 and what appear to be valid numbers for both int
> 21-7303 and 21-36.

>> Eric, Leland Holliday (sp?) told me that he reworked your
>> freetest.asm in that zip file and got it outputting correct numbers
>> (the numbers were bogus) and displaying usable output.