Date: Thu, 18 Sep 2014 20:51:33 -0400 From: Allan Jude <allanjude@freebsd.org> To: freebsd-hackers@freebsd.org Subject: Re: "Invalid partition table" on 10-stable. Message-ID: <541B7E15.1010201@freebsd.org> In-Reply-To: <1411078978.90616.21.camel@jill.exit.com> References: <1411013471.25791.52.camel@jill.exit.com> <541AB164.80707@beastielabs.net> <loom.20140918T225950-776@post.gmane.org> <alpine.BSF.2.00.1409190001590.873@laptop> <1411078978.90616.21.camel@jill.exit.com>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --2Xgnprejc7IoqGUNUQshQaElXw3kkX3Re Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 2014-09-18 18:22, Frank Mayhar wrote: > On Fri, 2014-09-19 at 00:03 +0200, Wojciech Puchar wrote: >>>> >>>> /sbin/gpart bootcode -b /boot/pmbr ada0 >>>> >>>> Probably gpart changed the way it installs the MBR, but I think it i= s >>>> very board (or maybe BIOS) specific: other systems do not have the i= ssue. >>>> >>>> Please let me know if this "trick" helps for you. >>> >>> I did install the pmbr during the initial setup, as well as the boots= trap >>> itself. I do plan to try the "set active partition" trick suggested >>> elsewhere. >> while it may not solve your problems i prefer to NEVER make MBR partit= ions=20 >> at all, only bsdlabel. >> >> example: >> >> [root@laptop ~]# bsdlabel ada0 >> # /dev/ada0: >> 8 partitions: >> # size offset fstype [fsize bsize bps/cpg] >> a: 249984 16 4.2BSD 0 0 0 >> b: 4750000 250000 swap >> c: 117210240 0 unused 0 0 # "raw" part,= don't edit >> d: 63332672 5000000 4.2BSD 0 0 0 >> h: 48877568 68332672 4.2BSD 0 0 0 >> >> simply do >> >> bsdlabel -B disk >> >> to make it bootable. >=20 > Well, my pmbr isn't really an MBR, it's just the fake one to make thing= s > "work right" as I understand it. In fact, I don't really understand it= , > or why it's necessary, but it's pretty clear that something's funky > here. >=20 > I'm planning to avoid disk/bsdlabel entirely in favor of gpart, GPT and= > zfs. (I'm dead set on using ZFS; I don't trust UFS nearly as much as I= > used to.) >=20 I think the reason it is necessary, and called a 'protective' MBR, is that when Windows sees a disk without a valid-looking MBR, it immediately offers to format it for you. Thus the pMBR prevents you from accidentally erasing all of your data if you boot windows of another drive or something. --=20 Allan Jude --2Xgnprejc7IoqGUNUQshQaElXw3kkX3Re Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (MingW32) iQIcBAEBAgAGBQJUG34YAAoJEJrBFpNRJZKfy4QP/1Dqesrk45H+thCZflW+kkBc MkaeWXBwvVDY5gN1qQ1sNyBXwosVKdpsSZpJJJEV34955tOkfgd54WK4g8pVKkrU iLR/3yvigm/WeoG7D8ogiizIZMG3QxHUTK83LuWp+bmj3koamgo+FnxsK4jh2dC3 1dxWugzRHaDNkqnTYfyGscIZhJ9GpD0GI+wIba7ydPs7RwZHgB4woV9Q3b+G8ebL K+Cbi269QURMuWuL6g2/h0pF3gaFiOlzx2cVoNPYoOtBf3EziStIXsk3xpTSdP+5 +UICaBSQKiOvHsge2jHbEdhEThjY45JmlMFABKBvviYQzH8pWWH0USYHnK2bEkWS Kxg+Xhw6F/WM+7bnFZrkfNYyjgxm7zSwNi1fOjXPx20caet1m37GDE/qEHSVJ0tz gagIH51TKE3xrgECT/Iv3JXQj1N9/R9/2OKZme7WU/XJpIyph8Jid8WHMcRrorwY H0dJmAMWsRQ1yiX/n3YK6xOSKGTAZkw5FkionO9HSfRf9IwcNg+Ob2EKowCICHRS a60rXccuwIcEW+pNQzFppj+12LGYg5F4+0l3JdMMoJ0qdtrIjf7n/LH9HW2OlWb3 F1mmwQFr550BKz46yHLEEJirJeJcGplPI55gpMtXvT3W1wqRBDBO6ZmY96THLxTX 8+ag+7p+pIFQaiEt2p36 =2XdH -----END PGP SIGNATURE----- --2Xgnprejc7IoqGUNUQshQaElXw3kkX3Re--
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