Date: Fri, 21 Oct 2016 03:43:01 +1100 (EST) From: Ian Smith <smithi@nimnet.asn.au> To: Kevin Oberman <rkoberman@gmail.com> Cc: Warner Losh <imp@bsdimp.com>, Rostislav Krasny <rosti.bsd@gmail.com>, freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: I'm upset about FreeBSD Message-ID: <20161021024744.B6806@sola.nimnet.asn.au> In-Reply-To: <CAN6yY1vbd0rwCXGopn5SZ3PGzqKf1ytFNJq4tX4%2Bd4Ktad%2BLeQ@mail.gmail.com> References: <CANt7McFNq%2BYSGc_9%2BH%2BUuTDO=df9Q29psRMVmiYR=q53DdBcRQ@mail.gmail.com> <CANt7McH2LmmU3Kn2f3_m-Cu=%2BdrVMyHFB%2BXAW5O5XzLhUH-MYQ@mail.gmail.com> <CANCZdfquRep=ffpMc74mTw2rjeSWPHWyNRcdNfvX=vBbLB0Dsg@mail.gmail.com> <CAN6yY1vbd0rwCXGopn5SZ3PGzqKf1ytFNJq4tX4%2Bd4Ktad%2BLeQ@mail.gmail.com>
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On Wed, 19 Oct 2016 16:38:09 -0700, Kevin Oberman wrote:
> On Wed, Oct 19, 2016 at 3:39 PM, Warner Losh <imp@bsdimp.com> wrote:
>
> > On Wed, Oct 19, 2016 at 12:21 PM, Rostislav Krasny <rosti.bsd@gmail.com>
> > wrote:
> > > On Tue, Oct 18, 2016 at 21:57:29 +1100, Ian Smith <smithi@nimnet.asn.au>
> > wrote:
> > >>
> > >> If FreeBSD GPT images (and Kindle readers) can trigger this, so could a
> > >> theoretically unlimited combination of data on block 2 of USB media;
> > >> modifying FreeBSD to fix a Windows bug should be out of the question.
> > >
> > > Not modifying FreeBSD and not fixing Windows bug but modifying the
> > > FreeBSD installation media and working around the Windows bug to let
> > > people install FreeBSD without disappointing at very beginning. Why
> > > GPT is used in the memstick images at all? Why they can't be MBR
> > > based? I think they can.
> >
> > Can't boot UEFI off of MBR disks on all BIOSes.
> >
> > Warner
>
> I'll go one farther. You can't boot many new PCs with traditional MBR
> disks. And. please don't confuse GPT with UEFI. I have yet to find an
> amd64 computer that has a problem with a GPT format with MBR. Due to broken
> BIOS, my 5-year old ThinkPad won't boot UEFI, but it has no problem with
> MBR, whether GPT formatted or not. As far as I know, the 11.0 memstick
> images are still MBR, just on a GPT structured disk, not UEFI. (Let me know
> if I am mistaken on this.)
Well, GPT with protective MBR. Wikipedia calls FreeBSD's GPT 'hybrid',
I gathered because it still works also with older BIOS booting.
root@x200:/extra/images # mdconfig -lv
md0 vnode 700M /home/smithi/FreeBSD-11.0-RELEASE-amd64-memstick.img
root@x200:/extra/images # gpart show -p md0
=> 3 1433741 md0 GPT (700M)
3 1600 md0p1 efi (800k)
1603 125 md0p2 freebsd-boot (62k)
1728 1429968 md0p3 freebsd-ufs (698M)
1431696 2048 md0p4 freebsd-swap (1.0M)
[wondering vaguely what use 1.0M of swap might be?]
> I do accept that some early amd64 systems and, perhaps, many i386 systems
> may have problems with GPT, but GPT was designed to be compatible with
> traditional disk formats and, while they may have problems, they really
> should work for single partition disks. And I understand that it is
> frustrating if you hit one of these cases where it fails.
My 8yo Thinkpad X200 knows nothing of UEFI and boots 11.0 amd64 memstick
fine as is. It also happily boots from a sliced MBR memstick w/ boot0,
after dd'ing md0p3 to (in this case) da0s2, adding bootcode after a bit
of fiddling recreating da0s2 & da0s2a after the above dd clobbers it ..
So it's not hard making an MBR sliced memstick with up to 4 bootables;
I'm hoping to convert dvd1 to one of these, maybe it'll work this time,
and - at least theoretically - couldn't "kill Windows" by mere presence.
cheers, Ian
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