Hi Mandeep,
Thank you for sharing your points and links. Appreciated your help.
On Mon, Oct 18, 2010 at 10:27 PM, Mandeep Sandhu <mandeepsandhu.chd@xxxxxxxxx> wrote:
> I have very little knowledge on how to create ramdisk. I don;t know muchI'm not sure what rootdisk means, but i guess it's the disk
> about rootdisk mean. Also, which one of these two is loaded first, when
> booting up a network system/device etc.
(hard-disk/flash etc) where your root directory lives.
ramdisk on the other hand is a filesystem image that can be loaded on
to the RAM. It emulates a block device in RAM and uses it as a backing
store for a regular FS. The regular FS's support must be built into
the kernel.
ramdisk is loaded first.
ramdisk image basically contains driver modules and other essential
>
> what are the contents goes to ramdisk & rootdisk?. Basically. I am looking
utilities which help the kernel load your actual root FS (aka
rootdisk).
Eg: if your root FS is on a SATA drive, then the kernel would need the
SATA driver for talking to the drive. It would also need the relevant
FS module (ext/ext3 etc) for reading/writing to the FS image on the
SATA drive. These modules will packaged as part of your ramdisk image.
I "think", initramdisk/initrd images have been superseded by the more
popular initramfs nowadays (not completely sure though).
"initramfs" does not require any FS support in the kernel. It is much
simpler than a "ram disk" image since it does not have to deal with
writing to backing store (which the ram disk was emulating), managing
buffers etc. Rather its not a FS at all, but a CPIO archive which is
unpacked by the kernel in ram and then accessed w/o the need of a FS.
You can read more here:
http://www.mjmwired.net/kernel/Documentation/filesystems/ramfs-rootfs-initramfs.txt
Yes its possible, provided your ramdisk has the relevant bits.
> for more information how to start a devices with these two.
> Is it possible to boot a device with ramdisk alone?
Eg a lot of embedded systems boot a ramdisk image with busybox in it.
HTH,
-mandeep
>
> Thanks in advance.
>
> Regards,
> SS.
>
--
Regards,
S. Sengottuvelan.
