|  | 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. |