Re: Debian Sarge on oldworld Powermac?
On Fri, Jun 11, 2004 at 07:16:08PM +0200, Ralf Schlatterbeck wrote:
> The floppy booting is a *very* erroneous process, I was usually
> successful booting from a floppy only after 5-6 tries.
The floppy driver in OF 1.0.5 doesn't have very good error handling. It
chokes on the slightest errors, even if the MacOS can read every bit.
One thing that sometimes helps is to only use freshly formatted floppies.
> Also once the mac-OS is gone, the boot floppies don't
> seem to boot anymore? So this is not a viable option, especially since I
> don't have any mac-OS disks to restart a system that doesnt have mac-OS
> on the hard drive.
The problem here is that once you setup quik (bootloader) in Linux, it
changes to OF config to boot directly from the hard drive, which prevents
it from doing the normal search for bootable devices. The problem is that
the search is actually done by the Apple ROM (/AAPL,ROM in OF), which is
the default boot device. They didn't fix this until the version of OF
found in newworld models.
> What I've achieved so far:
> - Booting into open firmware prompt with a serial line
The 7600 actually supports doing OF on the internal video and ADB keyboard
fairly well. However, it's likely to start up in some unusual video
settings, so you need a good monitor. Just set the input-device to
'kbd' and the output-device to '/chaos/control'.
> - Booting a self-compiled kernel off my internal network using bootp.
> I've probably set up everything correctly on the server side (I've
> successfully done a woody network install with an X86 based IBM X31
> laptop with a similar server-side dhcp/tftpd setup) but the open
> firmware won't start the kernel. According to messages it initializes
> text and data segment but fails on bss. Looks like the BSD people are
> able to boot oldworld via network, I'd really like to do this with
> linux, too.
> Note that a COFF instead of ELF kernel is needed for this to work.
This used to work. In fact, network booting worked before hard drives.
> My questions:
> - What magic incantations are needed for making open firmware 1.0.5 boot
> a linux image across the network?
I seem to recall that it was pretty picky about the bootp server. Of
course, you also need a COFF image. The netbsd folks have some pretty
good info about network boots. Take a look at some of the boot related
sections of http://www.netbsd.org/Ports/macppc/faq.html for more
details, including things like some of the syntax quirks of older
models (and the 7600 is one of the oldest with OF). Just remember
that you'll want vmlinux.coff anywhere they talk about ofwboot.xcf.
> - What magic incantation do I need for building a kernel (or are there
> pre-built COFF Kernels available for Debian sarge?)
It used to just work. The kernel build process can build a vmlinux.coff,
though from the complaints I've seen on some of the lists recently, I
wouldn't be surprised if that got broken. It doesn't get used much.
> - Or is there some magic for booting from CDROM with open firmware 1.0.5?
I don't think OF 1.0.5 is capable of booting directly from a CDROM. I
never saw any evidence of it, and I'm sure someone would have gotten
it to work if it was possible. The way to boot Linux from a CDROM on
an oldworld Mac is with miboot, which is also what the Debian boot
floppies use (I think). The image with miboot looks like a normal copy
of MacOS to the ROM, but it then proceeds to load a Linux kernel and
boot it. The only problem is that while you only need an HFS filesystem
with miboot for a floppy, you need drivers to write to the CDROM with
miboot in order to make a bootable CD. Commercial Linux vendors use
a commercial driver (available with Toast and other similar products),
but we can't do that. There is enough information available from
Apple to write an open source driver, but since this would be about
the only use of it, noone has done it.
> - Pointers to additional sources of information welcome.
Well, the netbsd.org page has a lot more info about OF on these old
boxes than any Linux page. If you search on Apple's developer site,
there is a reasonable amount of info about OF and some of the older
boot methods, but I'm not sure how helpful that would be.
I'm not sure if it goes back far enough, but you may find something
useful in the old linuxppc mailing list archives. Take a look at
http://lists.linuxppc.org/ for that. If you can find a decent
archive of the old linux-pmac list, that would be old enough to
go back to when everyone had to deal with this crap, because
bootx and miboot didn't exist yet, and there was only OF 1.0.5
in PCI powermacs.
Brad Boyer
flar@allandria.com
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