Re: [Etherboot-developers] booting non linux images

[Anuradha R. <anu...@be...>]

Dear Eric and Ken,

On Mon, 14 May 2001, Ken Yap wrote:

> If you know the load map of memtest86, it's fairly easy to write a
> routine for mknbi.pl to generate a tagged/ELF image. Look at sub
> mknbi_rom for the simplest example.

This is what I understand about memtest86 booting procedure. Please
correct me if I am wrong. I am trying to write a mknbi.memtest86 for that.

1. memtest86.bin contains 512 bytes of boot sector, 2048 bytes of
   of setup and the "real" code.

2. The os loads bootsector to the standard location (0x7c00) and
   transfers control to it.

3. The code in the boot sector duplicates itself at 0x90000 and jumps
   to the new location. It loads setup at 0x90200 (does it load the
   rest of the code at 0x10000?) and transfers control to the setup.

4. Setup does necessary initilizations, detects memory etc. (does it
   handle the loading of the rest) and transfers control to
   0x10000.

5. The code at 0x10000 moves the code in relo.out to memory above 0x100000
   etc. but we don't have to worry about this.

Now about tagged image...

1. First I write four bytes containing the magic number.

2. Then I write the header of the tagged image so that the tagged image
   contains two sections (setup and the rest of the code) and the starting
   and loading address of setup is given as 0x902000?

Will let you know the progress. Please let me know if I am making any
fundamental mistake.

Thanks again for your time.

Regards

Anuradha