Making a Windows disk a file on Linux

[Jason Stephenson]

You've gotten some good advice so far, but I just wanted to mention 
another alternative that I've done on several different systems, 
including GNU/Linux and FreeBSD.

If you really are interested in having a FAT32 or some specific 
filesystem available on a drive without repartitioning, then another 
workable solution is to create an empty file of the desirable size by 
using dd if=/your/file of=/dev/zero with other appropriate options. You 
can then format that file with a file system and mount it with the 
appropriate options. You can read and write to that file as if it were a 
regular filesystem. I've even used the above to make a "bootable" file 
for VMWare.

It has been a year or more since I've done that and the specifics vary 
by OS (lately, I've been using FreeBSD more for that sort of thing), but 
finding instructions was fairly easy on the 'Net last time I needed to 
look. Also, if prodded, I could probably get you the proper sequence of 
commands on your OS choice after a few minutes refreshing my memory with 
the man and info pages.