Re: [Etherboot-developers] image file format and BIOS use

[Ken Y. <ke...@nl...>]

|I see there are a lot of different image formats supported by the

More correctly, different target OSes.

|Etherboot code.  So far I have only seen the documentation for the
|tagged image format (mknbi) available via the Etherboot home page.  Can
|anyone give me suggestions/ideas on the best file format to use or the
|best way to go about this?  Basically the kernel file I want to boot is
|a plain vmlinux, except I need a way to specify kernel parameters (i.e.
|command line).  Also if you could point me to any links which describe
|the other file formats I would appreciate it.

Etherboot supports three loading formats, tagged, ELF and a.out. I'd
forget about a.out. Tagged is specified in the documentation, ELF in a
standards document from somewhere. Either one will fit your needs. Your
problem is really to change the startup routines to avoid/replace the
BIOS calls you don't have. For this look in mknbi/first32.C and the
assembler routines it calls. The BIOS calls used are for console I/O,
time of day, and sizing memory, if I recall correctly. You'll also need
PCI BIOS support if you have PCI Ethernet controllers.

BTW, the BIOS calls are not *to* to the Linux kernel as you assume. The
Linux kernel is not executing yet at that point. The BIOS calls are to
the BIOS ROM.