Understanding disk usage and need for Compressor

Hi,

I'm trying to understand the issue of trying (or the need to) to recover disk space in a virtual machine.

When I installed Parallels and Windows XP I chose the recommended "Expanding" and stipulated 32 GB.

This is my current status :

From Max OS X :

[C] winxp :
Capacity 31.24GB Available 25.02 GB Used 6.22 GB

winxp.hdd 21.31 GB on disk

In XP I see :

Drive C : Capacity 31.2GB Used 6.22 GB Free 25GB

Question

What is the implication of : "winxp.hdd 21.31 GB on disk" ?

(This amount is included in the 54.99 GB of used space in Macintosh HD.)

I'd appreciate comments. Thanks.

howardm