disk space (when i use cp)

[Pol Hallen <debianen@fuckaround.org>]

Hi all :-)

i have 1Gb free on my debian,
when i cp from ftp server to usb hd the space on my system decrease.. a lot.. 
and often is zero..

it's correct?! i copy to usb hd not system hd :-(

tnks :-)
 
Pol