On Fri, Dec 22, 2000 at 11:35:13PM -0600, Richard Rauch wrote:
> I have a hard drive that is 20GB (give or take a little).  It is generally
> recognized as such by NetBSD.  However, note the following:
> 
>  /~~~ dislable -r wd0a
> 
>  [...]
> bytes/sector: 512
> sectors/track: 63
> tracks/cylinder: 16
> sectors/cylinder: 1008
> cylinders: 16383
> total sectors: 40020624
> rpm: 3600
>  [...]
> 
>  \___ disklabel -r wd0a
> 

There are 2 limitations with PCs and IDE drives. The first one is the
BIOS interface limitation when using CHS (cylinder/head/sector) addressing.
The limit there is 1024/255/63. The other limit is the old controller
interface limit, which is 16383/16/63.

Due to these limits, reported CHS values will be smaller than the total
size of the disk if it's > 8G. Don't worry about this. Ignore the
CHS values, and only use the logical sector values instead when
using NetBSD. The kernel doesn't care about the CHS values, and
the bootblocks will not use them if the NetBSD partition lies above
8G (provided that the BIOS provides the extended int13 interface).

- Frank