Re: Problems with my partition table.(Second Times)

[Andrew Clausen]

Hi,

I don't know what happened to your first try... sorry!

Alberto Rodríguez wrote:
> 
>         First I'd like say you congratulations for this wonderfull program, I
> have read the documentation and I think it's great.
> 
> Well, my problem is that the CHS of my slave disk (hdb) on the sistem
> (linux) don't match with CHS on the Bios.
> 
> If I write fdisk /dev/hdb, in my system, I get this:
> 
> The number of cylinders for this disk is set to 1027.
> There is nothing wrong with that, but this is larger than 1024,
> and could in certain setups cause problems with:
> 1) software that runs at boot time (e.g., LILO)
> 2) booting and partitioning software from other OSs
>    (e.g., DOS FDISK, OS/2 FDISK)
> 
> Command (m for help): p
> 
> Disk /dev/hdb: 255 heads, 63 sectors, 1027 cylinders
> Units = cylinders of 16065 * 512 bytes
> 
>    Device Boot    Start       End    Blocks   Id  System
> /dev/hdb1             1       377   3028221   83  Linux
> /dev/hdb2           378       384     56227+   5  Extended
> /dev/hdb5           378       384     56196   82  Linux swap
> 
> Acording you documentation, CHS on the system and on the Bios must be
> the same, so I put the follow line when I boot my system:
> 
> LILO boot: linux hdb=16368,16,63
> 
> (The above CHS is the CHS I have seen when I check it in the Bios)
> 
> So my system boot and all look like OK, but if I write now, fdisk
> /dev/hdb, I get the follow lines:
> 
> The number of cylinders for this disk is set to 16368.
> There is nothing wrong with that, but this is larger than 1024,
> and could in certain setups cause problems with:
> 1) software that runs at boot time (e.g., LILO)
> 2) booting and partitioning software from other OSs
>    (e.g., DOS FDISK, OS/2 FDISK)
> 
> Command (m for help): p
> 
> Disk /dev/hdb: 16 heads, 63 sectors, 16368 cylinders
> Units = cylinders of 1008 * 512 bytes
> 
>    Device Boot    Start       End    Blocks   Id  System
> /dev/hdb1             1      6009   3028221   83  Linux
> Partition 1 does not end on cylinder boundary:
>      phys=(376, 254, 63) should be (376, 15, 63)
> /dev/hdb2          6009      6120     56227+   5  Extended
> Partition 2 does not end on cylinder boundary:
>      phys=(383, 254, 63) should be (383, 15, 63)
> /dev/hdb5          6009      6120     56196   82  Linux swap
> 
> And this is the problem.
> 
> Is there any way to get that Bios's CHS and System's CHS match each
> other without getting the last message?

Option 1: change the BIOS's CHS to match Linux's.

Option 2:
ignore the problem, and use LBA mode for booting, etc.

The problem was caused by using fdisk (i.e. linux) to do partitioning.
It had Linux's idea of the partition table (as parted would have had),
which was different to the BIOSes.  However, now that you have your
partition table inconsistent with the BIOS, there is little you
can do about it.  If everything works, then I wouldn't bother
changing anything!  (LILO/GRUB/whatever is using LBA?)

Andrew Clausen