Copying files to USB drive (w LiveCD) takes up **memory space**

[Mark Gilmore]

When I copy a sizable file to a thumb drive (using Live CD),
my free memory space decreases by the approx size of the file.
I can verify this by entering the "free" command before and
after the copy.
Assuming a caching issue, I tried forcing the drive to mount
in "sync" mode (via an fstab edit), but this had no effect.
Perhaps this is some kind of unionfs issue/bug ?
I can't install Ubuntu onto a flash drive because the system
runs out of memory and the install program dies.
Thanks !
-- 
Mark Gilmore
http://OmnipotenceSoftware.com