Subject: Re: Prep bootloader
To: Tim Rightnour <firstname.lastname@example.org>
From: David Brownlee <abs@NetBSD.org>
Date: 03/11/2006 10:53:19
On Fri, 10 Mar 2006, Tim Rightnour wrote:
> On 08-Mar-2006 Jochen Kunz wrote:
>> I have to admit to be quite clueless in the bootloader department. How
>> hard is it to build a bootloader that reads a kernel image file from
>> FFS? I suppose most of FFS handling is in some kind of MI lib. So it may
>> be "just a bit if glue code" to do the actual IO via firmware calls. Is
>> there a firmware interface for device independent IO? (All I know is a
>> bit OpenFirmWare and the hp700/hppa PDC.)
> So.. I've done some investigation on the bootloader, and come up with something
> rather disturbing.
> The PReP spec quoteth:
> "Conventional firmware must not export any entry point for call-back to
> This means we are essentially fscked. When they say "conventional firmware"
> they mean prep firmware, as opposed to actual Open Firmware. A second stage
> bootloader would essentially need a standalone scsi driver, (possibly requiring
> a PCI layer) a standalone ISA IDE driver, and maybe even network support.
> All of this means.. I think we are back to my original idea here. We just need
> to make mkbootimage as painless as possible to use, and train sysinst to use it.
Another option would be to support something like kloader(4), then
your 'bootloader' becomes a kernel. Its unlinkely the benefits
of that outweigh the effort though...
David/absolute -- www.NetBSD.org: No hype required --