80G disk seen as 20G?

[Victor Munoz <vmunoz@macul.ciencias.uchile.cl>]

 Hello. I have a new machine running Woody, kernel bf2.4, and
I noticed my 80G hard disk is only 20G, according to df -h. What could be
happening? I've read about issues with disks larger than 34 G, which could
cause that behavior
(http://www.tldp.org/HOWTO/Large-Disk-HOWTO-12.html#verylarge),
but I also understood that is solved in the 2.4 kernel series.

dmesg says it's 80G anyway:

spl09:/home/vmunoz# dmesg | grep hda
    ide0: BM-DMA at 0xffa0-0xffa7, BIOS settings: hda:DMA, hdb:pio
hda: ST380011A, ATA DISK drive
hda: 156301488 sectors (80026 MB) w/2048KiB Cache, CHS=155061/16/63
 hda: [PTBL] [9729/255/63] hda1 hda2

but df tells otherwise:

spl09:/home/vmunoz# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/hda1              18G  4.8G   12G  28% /

I have another machine with the bf2.4 kernel, 40G hard disk, and
it is recognized as such by df.

Ideas? Thanks in advance,

						Victor