Information about the Linux/PPC kernel images
=====================================================================

Please mail me (Cort Dougan, cort@fsmlabs.com) if you have questions,
comments or corrections.

This document is meant to answer several questions I've had about how
the PReP system boots and how Linux/PPC interacts with that mechanism.
It would be nice if we could have information on how other architectures
boot here as well.  If you have anything to contribute, please
let me know.


1. PReP boot file

  This is the file necessary to boot PReP systems from floppy or
  hard drive.  The firmware reads the PReP partition table entry
  and will load the image accordingly.

  To boot the zImage, copy it onto a floppy with dd if=zImage of=/dev/fd0h1440
  or onto a PReP hard drive partition with dd if=zImage of=/dev/sda4
  assuming you've created a PReP partition (type 0x41) with fdisk on
  /dev/sda4.

  The layout of the image format is:

  0x0     +------------+
          |            | PReP partition table entry
          |            |
  0x400   +------------+
          |            | Bootstrap program code + data
          |            |
          |            |
          +------------+
          |            | compressed kernel, elf header removed
          +------------+
          |            | initrd (if loaded)
          +------------+
          |            | Elf section table for bootstrap program
          +------------+


2. MBX boot file

  The MBX boards can load an elf image, and relocate it to the
  proper location in memory - it copies the image to the location it was
  linked at.