recompiling kernel help

[botoo]

Hi all,
I like to recompile kernel. I know there is lots of instruction on net, but i need to clarify what i am doing. I have software raid on /dev/md1as raid1(/boot) and /dev/md3 as raid0(/) . when i try to boot to live cd or minimal cd, they dont automatically recognize my raids. So i have trouble mounting them to /mnt/gentoo. Can i recompile kernel in currently running system by going to /usr/src/linux? I have tried doing that and booted to new kernel image, and somepoint it failed to boot as failing to mount root system and cant reconize fs. anyway, I also have problem with dma with my dvd drive. so anywhere i have to enable dma in kernel. below is what i got when i try to enable dma on dvd.
hdparm -d1 /dev/hdc

/dev/hdc:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma = 0 (off)

Thanks in advance

[fangorn]

Let me make this clear you want to recompile the kernel of the livecd

There is pretty much docu on installing gentoo to RAID/LVM/DM_CRYPT devices out there (I'd start at DT&T and gentoo-wiki.com). Read one of these, follow the instructions thoroughly and you will get your system up and running. This task is too complex to describe here.
_________________
Video Encoding scripts collection | Project page

[botoo]

Thanks for reply,
I got to stage to be able to mount software raid by reading mdadm manual again.
>mdadm /dev/md1 -A /dev/sda1 /dev/sdb1
after i compile kernel, I copy arch/i386/boot/bzImage /boot/TestKernel, and edited grub.conf, as below

title=Gentoo
root (hd0,0)
kernel /boot/kernel root=/dev/md3

title=TestKernel
root (hd0,0)
kernel /boot/TestKernel root=/dev/md3

BUT, when i choose to boot TestKernel, it said somewhere,
VFS: Cannot open root device "md3" or unknown-block(2,0)
and Kernel panic.

Is there any thing I need to do more?

[botoo]

looks like i got it boot again,
wrong driver for SATA in kernel was the fault.