IDE drives mis-reporting size... bug or feature?

[Josh Fryman <fryman@cc.gatech.edu>]

hi all,

this is an odd one.  i think it's technically a feature
but might be perceived instead as a "bug".  anyway, i've
got a pair of Ultra100 Maxtor 52049h4 20GB drives, on a 
Promise Ultra 100 (PDC20267) controller.  

the drives were popped in with the jumper on for the
4096 cylinder limit forced.  (it's a long story as to why.)
the other jumpers were set normally for master/slave config.

the promise controller recognizes the drives on boot-up
init as being what they are - ~20GB - and continues on
merrily.  

Windows 2000 recognizes the drives as ~2GB in size, due to
the jumper.  it's observing the 4096cyl limit on the drive
in some way.  (remove the jumper and it sees ~20GB too.)

Linux 2.4.3 recognizes the drives as ~20GB regardless of
the jumper.

so, is this a bug or feature?  is windows or linux not 
working right here?  what *should* be seen with the drive
jumpered such?

cheers,

josh