Re: [gentoo-user] Cannot open root device "sda3" or unknown-block (0,0)

[Joseph]

On 11/16/10 21:04, Dale wrote:
>Joseph wrote:
>> My ASUS A8V motherboard went down so I change it with another ASUS MB
>> M2NPV along with CPU. Both CPU's were AMD so no need to change flags.
>> Have two hard drives both SATA 200G and 500G
>> However, after trying to boot I get:
>>
>> VFS: Cannot open root device "sda3" or unknown-block (0,0)
>>
>> In grub.conf I have:
>> root (hd0,0)
>> kernel /boot/kernel-current root=/dev/sda3 pci=noapi noapci
>> When I boot strap and run, df -h it shows all the partition correctly
>> but all showing as:
>> Size: 46G used: 30G avail: 15G
>>
>> So it would seem to me the kernel does not recognized correctly large
>> disk drives; but it this kernel worked correctly with previous
>> motherboard (the one that failed).  BIOS is showing both hard drives
>> size: 200G and 500G
>> What to look for?
>>
>
>I would start by checking the kernel config.  Make sure you have your
>drive chipset BUILT INTO the kernel and whatever drivers you use for the
>file system root is on also BUILT IN.  Keep in mind, you can't build
>those as modules.  They have to be in the kernel itself.
>
>As to the different sizes, not sure.  Maybe someone who has seen that
>will have additional ideas.  May be driver related, may be something else.
>
>Dale
>
>:-)  :-)

The BIOS sees both HD but, boot sector is working OK as grub comes up but then I get a message:

VFS: Cannot open root device "sda3" or unknown-block (0,0)
please append a correct "root=" boot option; here are the available partitions:
0300  4191302 hda driver: ide-cdrom

So it seems kernel does not see the sata drives, but how it is possible? Boot partition is on sda

Someone suggested that BIOS is seeing different logical layout of cylinders/ heads.
In BIOS setup there a choice of IDE mode, AHCI mode, etc 

-- 
Joseph