Thanks a lot! I understand a lot now. But one thing I want to
ask Jesse Off. In his reply:
"/dev/mtdblock1 is not even the real device name -- it
becomes /dev/mtdblock/1 when the real /dev is mounted.
"
Is it a special mapping for TS-Linux kernel only or all other
embedded Linux distributions do the same translation? Has that board
design company changed kernel so that it can know "/dev/mtdblock1" is
actually "/dev/mtdblock/1" after mounted? If i want to boot from CP
or USB or something external, which device under /dev/ directory
should I use?
Tom
--- In wrote:
>
> Quoting chentom60 <>:
>
> > Hello,
> >
> > I have some stupid confusions on loading kernel from flash,
please help
> > me to clarify:
> >
> > 1. why 0x00218000
> > Why is this address selected to save kernel in Ram, is there any
> > special reason?
>
> The firmware has to know where the image is in RAM, since the
> exec command doesn't take an address parameter, it either has to
> be hard-coded or specified via a firmware variable.
>
> >
> > 2. The subsequent exec -c "console=ttyAM0,115200
root=/dev/mtdblock1".
> > It looks like before kernel is executed, file system is already
> > available, otherwise there should be no /dev/ files. Who made the
file
> > system before Kernel is running?
>
> Obviously the kernel can't reference /dev on a filesystem until
> the filesystem is mounted. This implies the kernel has to have some
> built-in knowledge about certain /dev devices for root mount
purposes.
> Hint: look for /dev/mtdblock1 on the mounted root filesystem,
> you won't find it
> Also, think about /dev/nfs for an NFS mounted root filesystem, again
> the kernel has to have built-in knowledge about certain device
files.
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