[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Changing bootstrap method for NewWorld Power Macs

Hi Mark,

On 12/31/18 00:49, Mark Cave-Ayland wrote:
On 30/12/2018 21:01, Frank Scheiner wrote:
Open Firmware (IEEE 1275) can actually also boot from FAT file systems and this is
also supported on NewWorld Power Macs.

Unfortunately not everyone uses Open Firmware, and in particular OpenBIOS provided
with QEMU doesn't currently support FAT filesystems. So as the QEMU macppc maintainer
this change would then immediately cause the latest Debian images to fail to boot,
which is not something I can get excited about.

Sorry to hear that, though I think you need to provide additional details at this time:

What do you mean with "Debian images"? Because if you speak of the installer ISOs, my changes won't change anything with their ability to boot on NewWorld Power Macs or QEMU (I think).

My changes also do not remove existing code related to HFS as bootstrap. I expect that you will be able to still create all relevant partitioning and file systems manually from within the Debian installer, if needed to make it work under QEMU.

Please also realize that the original idea was to support GRUB installations on NewWorld Power Macs, something that doesn't work (automatically from the Debian installer) at the moment. To be completely honest, if we no longer need to depend on specific non-generic code, at the same time, I won't reject that.

Other point: why can't you directly load kernel and initramfs with QEMU?

Whilst I think this is a clever hack

What makes one bootstrap method a hack and the other one the "right" thing? I'm more interested in getting things working. :-) Actually I'd even recommend to use network boot where possible, because then you don't have to care about partitioning and on-disk file systems at all. This simplifies things so much.

, pretty much all of the bootsectors I see for
macppc across all OSs are either ISO9660 or HFS.

Please give some examples, because I know of a few second stage bootloaders - assuming you speak of that - that support both HFS or FAT16 as bootstrap FS: e.g. OpenBSD's and most likely also NetBSD's ofwboot, GRUB (and maybe also yaboot - at least it worked for SLES11 on ppc64 POWER, see [1]) so pretty much any Linux that runs on NewWorld Power Macs will be able to work with both FAT16 or HFS as bootstrap.

[1]: https://www.ibm.com/developerworks/community/forums/html/topic?id=eca44085-62e8-45b9-ac8d-a572d7dd999a

It's more a matter of how much preparation work is needed by users to get one or the other method going.

This makes me nervous that the
reason people have avoided switching to FAT before now is because either the
FAT-related drivers still have endian-related bugs, or not all Apple Open Firmwares
are bug free in this area. If it really is that simple, why isn't everyone doing it?

Maybe that information is just not widely known? Maybe people like to support both Mac OS X and Linux/*BSD on the same disk - something I didn't want to support this time, the least because of all the things that can go wrong with such a setup.

Speaking of bugs, we indeed have some bug(s) with hfsprogs on G5 Power Macs, see [2] for example.

[2]: https://lists.debian.org/debian-powerpc/2018/12/msg00053.html

Can you remind me again what were the problems that you were experiencing with HFS
under GRUB?

In addition to the issues I described in my previous message, also see [2].


Reply to: