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Re: How does linux boot

On Fri, 22 Oct 2004, Ritesh Raj Sarraf wrote:

> Now here is what confuses me !
> Say, My machine has a scsi disk in it. In normal scenarios it's obvious that
> I'll be using a modular kernel with initrd support shipped by my Linux
> distribution vendor. Fine till now.
> OS installation is done.. The kernel image, the initrd image etc are all
> stored on the disk.
> Now the boot loader loads and then loads the kernel image along with the
> initrd image.
> So, Is the boot-loader so smart and powerful (much more that the kernel) that
> it reads data from the disk without knowing the type of disk and the
> filesystem type ? I mean the kernel requires modules to be loaded to detect
> the type of disk (scsi or ide) , type of filesystem etc.. The boot-loader
> doesn't require anything ?  Amazing.
> If yes, the boot-loader is smart enough. Why not use it's master-piece code
> into the kernel ? :-)

from "The Linux BootPrompt-HowTo" you get:
  The kernel has a limited capability to accept information at boot in
  the form of a `command line', similar to an argument list you would
  give to a program. In general this is used to supply the kernel with
  information about hardware parameters that the kernel would not be
  able to determine on its own, or to avoid/override the values that the
  kernel would otherwise detect.

  However, if you just copy a kernel image directly to a floppy, (e.g.
  cp zImage /dev/fd0) then you are not given a chance to specify any
  arguments to that kernel. So most Linux users will use software like
  LILO or loadlin that takes care of handing these arguments to the
  kernel, and then booting it.

Take also a look in kernel-documentation e.g. 

... don't touch the bang bang fruit

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