Date: Sun, 11 Mar 2012 10:48:00 -0500 From: Nathan Whitehorn <nwhitehorn@freebsd.org> To: Rob Ballantyne <robballantyne3@gmail.com> Cc: freebsd-ppc@freebsd.org Subject: Re: Question about bootup Message-ID: <4F5CC930.9060001@freebsd.org> In-Reply-To: <CAKLrb5d=fos09L0fHY3Qdf4YRZ5FYBmHTV21iMzEybB65DpoSw@mail.gmail.com> References: <CAKLrb5d=fos09L0fHY3Qdf4YRZ5FYBmHTV21iMzEybB65DpoSw@mail.gmail.com>
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[Not replying to the top bits, since the others covered that correctly] On 03/06/12 00:24, Rob Ballantyne wrote: > Hi All, > > I've been poking around trying to understand the boot up process of > a ppc64 G5 machine. > > I was slightly surprised to still find an Apple Partition map disk. > I would have thought it was an ordinary fdisk (PC) partition setup. > > Let me see if I have it right: > > 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 > > ... and we're off to the races. > > 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? > > 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. > It is written by the installer, in the partition editor. You can see what it does by looking at /usr/src/usr.sbin/bsdinstall/partedit/partedit_powerpc.c. It just dd's a preformatted HFS partition from /boot/boot1.hfs onto the bootstrap partition. -Nathan
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