Re: ELKS 0.0.81 available from ftp.ecs.soton.ac.uk

[David Murn]

On Sat, 13 Nov 1999, Blaz Antonic wrote:

> All you have to do is to insure your ROM image uses correct format
> (utils in netboot package create correct images from executable
> binaries) and BIOS will do the rest of the job

Actually, 'format' simply means 0x55aa at the start of the image, and the
3rd byte contains the number of 256 byte pages in the ROM.  Nothing else
is involved in the 'format'.

> it will detect the ROM fetch its size and start address and start
> executing code from it. It is up to you (ROM) to return control to BIOS
> (and let it boot normaly) or execute kernel and boot into your OS
> (that's the way you want it if you imaplnt a ROM inthere).

I'd suggest that you don't do it this way, and that you actually hook
interrupt 0x19.  This allows BIOS to detect various hardware, and call any
other important ROMs, such as video and disk controller.  While you (in
theory) can boot directly from the ROM, ELKS won't like you much.  Apart
from anything else, quite a few drivers, notably the disk and console
drivers generally use BIOS calls.

Davey