From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 76C4F158089 for ; Wed, 18 Oct 2023 13:58:04 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 07BFC2BC090; Wed, 18 Oct 2023 13:57:59 +0000 (UTC) Received: from ciao.gmane.io (ciao.gmane.io [116.202.254.214]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id C3DA12BC08B for ; Wed, 18 Oct 2023 13:57:58 +0000 (UTC) Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1qt73d-0007W8-M5 for gentoo-user@lists.gentoo.org; Wed, 18 Oct 2023 15:57:57 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: gentoo-user@lists.gentoo.org From: Grant Edwards Subject: [gentoo-user] Re: OFF TOPIC Need Ubuntu network help Date: Wed, 18 Oct 2023 13:57:51 -0000 (UTC) Message-ID: References: <17dbcf2a-13c7-b8c0-69f1-a09e5288cfd5@gmail.com> <452fc599-ce6c-3bf9-4ad8-e253a94439c7@gmail.com> <20231018083606.7ebd2d77@digimed.co.uk> <2581583.Lt9SDvczpP@rogueboard> User-Agent: slrn/1.0.3 (Linux) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply X-Archives-Salt: 5f1b7dfc-76fa-4516-853d-ab46291c7f1f X-Archives-Hash: 305fd189783615018cb0d4533663c6c4 On 2023-10-18, Michael wrote: >> Oh, and if you use GPT, you no longer need the MBR compatibility >> partition, or whatever its called. I no longer need it so I can't >> remember the exact name. > > Man pages of partitioning tools refer to it as "Protective MBR", although I've > seen it mentioned in the interwebs as "protective GPT", which I think is more > accurate. It uses the first sector (LBA 0) to store an MBR table showing the > whole disk, or 2TB if smaller, as an MBR partition. This is the first > partition on the disk, typically 1 MiB in size. It is meant to stop 20 year > old partitioning tools from messing up a GPT partitioning scheme because they > can't see it. Arguably nobody uses Windows 98 these days, so it should be > safe to not have a protective MBR on your GPT disks. The protective MBR and the BIOS boot partition are two different, unrelated things. The BIOS boot partition is a real partition (usually 1-2MB in size) that's present in the GPT parition table. It's used by Grub as a place to store its files. It must be the first partition, and it doesn't have a real filesystem (grub uses some sort of private filesystem): $ sudo fdisk -l /dev/nvme0n1 Disk /dev/nvme0n1: 465.76 GiB, 500107862016 bytes, 976773168 sectors Disk model: Samsung SSD 980 PRO 500GB Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: gpt Disk identifier: E81DD16A-A5AE-3C4A-AD3C-26DF2985827A Device Start End Sectors Size Type /dev/nvme0n1p1 2048 6143 4096 2M BIOS boot /dev/nvme0n1p2 6144 134219775 134213632 64G Linux filesystem /dev/nvme0n1p3 134219776 976773134 842553359 401.8G Linux filesystem