From owner-freebsd-hackers@FreeBSD.ORG Mon Jun 11 19:58:04 2007 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 3718B16A47E; Mon, 11 Jun 2007 19:58:04 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from mail-out3.apple.com (mail-out3.apple.com [17.254.13.22]) by mx1.freebsd.org (Postfix) with ESMTP id 4B31813C4C7; Mon, 11 Jun 2007 19:58:02 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from relay7.apple.com (relay7.apple.com [17.128.113.37]) by mail-out3.apple.com (Postfix) with ESMTP id B4B08888FC5; Mon, 11 Jun 2007 12:40:14 -0700 (PDT) Received: from relay7.apple.com (unknown [127.0.0.1]) by relay7.apple.com (Symantec Mail Security) with ESMTP id 259E2300AC; Mon, 11 Jun 2007 12:41:19 -0700 (PDT) X-AuditID: 11807125-9ef62bb000000801-12-466da55eb1af Received: from [17.214.13.96] (cswiger1.apple.com [17.214.13.96]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by relay7.apple.com (Apple SCV relay) with ESMTP id E1EAD30063; Mon, 11 Jun 2007 12:41:18 -0700 (PDT) In-Reply-To: <86zm37v4ns.wl%rpaulo@fnop.net> References: <4AB3C4C0-0DA1-482F-A4CD-375A53332F29@mac.com> <4D7CDA24-48FE-4319-A320-C8D7165E9EBC@mac.com> <200706092128.l59LSjRs027671@apollo.backplane.com> <57F8CCC1-1841-41AE-9F82-0C87FE53BE99@mac.com> <200706101752.l5AHqdE0035954@apollo.backplane.com> <8B01C1EC-D61A-484F-B308-6D6C8EB00EE6@mac.com> <861wgjwnrw.wl%rpaulo@fnop.net> <200706102143.l5ALhQut038340@apollo.backplane.com> <86zm37v4ns.wl%rpaulo@fnop.net> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Content-Transfer-Encoding: 7bit From: Chuck Swiger Date: Mon, 11 Jun 2007 12:41:18 -0700 To: Rui Paulo X-Mailer: Apple Mail (2.752.2) X-Brightmail-Tracker: AAAAAA== X-Mailman-Approved-At: Mon, 11 Jun 2007 20:09:15 +0000 Cc: freebsd-hackers@freebsd.org, Marcel Moolenaar , freebsd-current@freebsd.org, freebsd-geom@freebsd.org Subject: Re: GPT - (last) call for action X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Jun 2007 19:58:04 -0000 Hi, all-- On Jun 10, 2007, at 3:13 PM, Rui Paulo wrote: >> :Media sector size is 512 >> :Warning: BIOS sector numbering starts with sector 1 >> :Information from DOS bootblock is: >> :The data for partition 1 is: >> :sysid 238 (0xee),(EFI GPT) >> : start 40, size 409600 (200 Meg), flag 0 >> : beg: cyl 0/ head 0/ sector 41; >> : end: cyl 406/ head 6/ sector 14 >> >> I think I have it mostly figured out, but the 'start 40' in your >> output can't be right. The intel documentation says that the >> starting LBA in a PMBR record must be set to 1 by definition >> (table 11-7 in the 1.10 documentation). > > I don't know why Apple does that. The offset of 40 sectors sounds like it is pointing to the first partition listed within the GPT? A typical Intel Mac system using GPT ought to look something like this: # fdisk /dev/rdisk0 Disk: /dev/rdisk0 geometry: 9964/255/63 [160086528 sectors] Signature: 0xAA55 Starting Ending #: id cyl hd sec - cyl hd sec [ start - size] ------------------------------------------------------------------------ 1: EE 1023 254 63 - 1023 254 63 [ 1 - 160086520] 2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused 3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused 4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused # gpt -r show /dev/rdisk0 start size index contents 0 1 PMBR 1 1 Pri GPT header 2 32 Pri GPT table 34 6 40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B- xxxxxxxxxxxx 409640 159414704 2 GPT part - 48465300-0000-11AA-AA11- xxxxxxxxxxxx 159824344 262151 160086495 32 Sec GPT table 160086527 1 Sec GPT header The first, small partition is almost certainly a "boothfs" boot partition, as described in the man page for Apple's version of fdisk: " In the default template, partition number 1 will be configured as a Dar- win boot partition spanning from cylinder 0, head 1, sector 1, and extending for 8 megabytes. Partition number 2 will be configured as a Darwin HFS partition spanning the rest of the disk. This mode is designed to initialize an MBR the very first time, or when it has been corrupted beyond repair. You can specify other default partition styles with the -a flag. The available styles are: boothfs Creates an 8Mb boot partition (type AB hex) and makes the rest of the disk a Darwin HFS partition (type AF hex). bootufs Creates an 8Mb boot partition (type AB hex) and makes the rest of the disk a Darwin UFS partition (type A8 hex). hfs Makes the entire disk one Darwin UFS partition (type A8 hex). ufs Makes the entire disk one HFS+ partition (type AF hex). dos Makes the entire disk one DOS partition (type 0C hex). raid Makes the entire disk one type AC hex partition. The -u flag is used to update the MBR code on a given drive. The MBR code extends from offset 0x000 to the start of the partition table at offset 0x1BE. It is similar to the -i flag, except the existing parti- tion table is preserved. This is useful for writing new MBR code onto an existing drive, and is equivalent to the DOS command ``FDISK / MBR''. Note that this option will overwrite the NT disk signature, if present. The -u and -i flags may not be specified together." Also cf: http://en.wikipedia.org/wiki/GUID_Partition_Table -- -Chuck