>> the Maxtor_6L120P0 is purportedly a 120gb disc, indeed the one i have
>> here says so on its label, however fdisc claims it only has 33.8 GB.
>> fdisk seems to have a command to change the number of cylinders, i
>> tried that, whereupon fdisk shows the given new number of cylinders,
>> but still shows the total number of sectors as unchanged, and won't
>> create a partition that goes beyond the original number of sectors, so
>> what's the point of the fdisk cylinders command, it's not at all clear
>> to me.  do i really have a 120gb disc here?  if so, how do i start
>> using all 120gb?  any clues/ideas?
>
> Are your jumpers on the right pins? Don't some disks have jumpers to
> limit the size they report so that old BIOSes can handle them?
>
> Also, google found something familiar
> http://forums.anandtech.com/showthread.php?t=1534455 (searched for
> "33.8 gigs")

yeah that was the first thing i checked, there is a jumper spot
labeled "cap lim".  but, no jumper there.  further fiddling with
google finally found a recommendation that hdat2 fixed such a problem.
 trying to boot hdat2 with memdisk got problems that sure looked like
memdisk doesn't really work, but memdisk booted ubcd511.iso just fine,
and the hdat2 in there removed the HPA from the drive in a jiffy.
yay!