Date: Mon, 5 Mar 2012 23:20:36 -0800 From: Jeremy Huddleston <jeremyhu@freedesktop.org> To: Rob Ballantyne <robballantyne3@gmail.com> Cc: freebsd-ppc@freebsd.org Subject: Re: Question about bootup Message-ID: <7CCF8382-BE98-4C0E-8EC5-096753CCA84A@freedesktop.org> In-Reply-To: <CAKLrb5d=fos09L0fHY3Qdf4YRZ5FYBmHTV21iMzEybB65DpoSw@mail.gmail.com> References: <CAKLrb5d=fos09L0fHY3Qdf4YRZ5FYBmHTV21iMzEybB65DpoSw@mail.gmail.com>
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#1 should be expanded a bit, and hopefully this will satisfy your = curiosity about the Apple_bootloader partition. =20 OpenFirmware itself is quite complicated. The "normal" situation is = that you have boot-device=3Dhd:2,\\:tbxi and the second partition on = your boot drive is an HFS partition (the first partition is actually the = partition map). One of the files on this HFS partition is "blessed" in = order to tell OFW to load it. In actuality, it's not a file that is blessed, but a directory in the = HFS partition, and that directory is inspected for a file of the type = "tbxi" which is loaded. In practice, there are usually no = subdirectories, so : is blessed, and there are only a handful of files, = one of which is either a bootloader or stage-1 kernel, and it is marked = "tbxi" using hfsutils or some other tools (eg: 'hattrib -b : && hattrib = -t tbxi -c UNIX :grub' will bless : and mark grub as the bootloader). I'm not an expert on all of this, so there is probably room for = expansion on some of my points, but hopefully that gets you in the right = direction. --Jeremy On Mar 5, 2012, at 10:24 PM, Rob Ballantyne <robballantyne3@gmail.com> = wrote: > Hi All, >=20 > I've been poking around trying to understand the boot up process of > a ppc64 G5 machine. >=20 > I was slightly surprised to still find an Apple Partition map disk. > I would have thought it was an ordinary fdisk (PC) partition setup. >=20 > Let me see if I have it right: >=20 > 1 - OpenFirmware (OFW) load Apple_Bootstrap/boot1.elf > 2 - boot1.elf runs to gain enough to understand UFS filesystems and > loads FreeBSD UFS partition /boot/loader > 3 - loader loads /boot/kernel/kernel >=20 > ... and we're off to the races. >=20 > This strikes me as fairly simplistic so I'm sure there are more > details. I'm curious about /boot/*.4th OpenFirmware forth code, for > example. Is it involved in a substantial way? >=20 > The other thing I'm curious about is the Apple_Bootstrap partition. > How is it written? I've discovered parteditor within the bsdinstall > installer. I suspect that does it but it doesn't appear to let one > write their own bootloader code image. >=20 > As I said mostly curiosity and trying to understand. If anyone has > a few words of confirmation/advice I would be glad to hear them. >=20 > Thanks, >=20 > Rob > _______________________________________________ > freebsd-ppc@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-ppc > To unsubscribe, send any mail to "freebsd-ppc-unsubscribe@freebsd.org" >=20
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