From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id CC0881382CD for ; Sat, 25 Jun 2016 20:19:34 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 4F29B94245; Sat, 25 Jun 2016 20:19:14 +0000 (UTC) Received: from mail-it0-f47.google.com (mail-it0-f47.google.com [209.85.214.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 3CFAC9423F for ; Sat, 25 Jun 2016 20:19:13 +0000 (UTC) Received: by mail-it0-f47.google.com with SMTP id g127so39068075ith.0 for ; Sat, 25 Jun 2016 13:19:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=HhNPt0SL2ZfOlq4/SLmYsgj7hQ0NZdQC+I0P//Al08Y=; b=y14aSaOSiw44SAXM+BAFNRKE9etPpOV0NKjwI1RsJCTC+vjJq4Nq1w2Qnt79TGl2U8 7R7anfOINSp5hsedzoo06T07Feck6JsvrC+k4zDF9FWkUlVePE/EbT3yPNx7KBDxhNZ1 MKhUEkyUkH1fbGiOCQf/xd0QGWBYr5ybuQcyM4n7Wqv1UnpWxpfAT+5AYE971fViSh5t mmtBdItsdtCP/rGJmvNvErY0lWluDtoXx0PTnh2Qce5a/SUyixnfvXnM+BWvkS5HR+4D Net9Cgn//p5B4QgUm6gLSDxFNuS0Xv9T5RptAwiZ6lcUEj7hBcr16qmNoZz8M2Ba7KVW AUAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=HhNPt0SL2ZfOlq4/SLmYsgj7hQ0NZdQC+I0P//Al08Y=; b=iJuIBDWbcRUUGkJ+JxHi2eLkCM8sPyeTlzPvbUZiPbbG9plwSk6z8SynETAi/8WlGH HXz4/z/3s+lCFuPodL/nk8amZp8DGPsaoWtixSAORvX79r+OD7C2alZXoyXLO6hQKPwL IiuvEY9/YE1yp/JagEl2LFj1B501dFM7slDqrpImIIzjJ08jbNGvlIBWweLvAIUVmw9Z brU740/E5oo66kytenG4sUz6CEf4rk9BxQ+yeP4LzEhUTeMZEO/Rg7nqiNPrrXMnD8ZP Loscd4z9IAVhJWXIwLDFi7QSwq4YR3B8ilFgvo/UxyrAd9dFyyaPN8bCwbLLfAjEZ13T GSqg== X-Gm-Message-State: ALyK8tLfhZlYbbZ9tQaGKTCWrZ3MV5U2dA2h1yKz+blVDOqU8LjVZpg9BeIS4F1XAe1tzx/6FVjrhu7bvKzCBg== X-Received: by 10.36.121.70 with SMTP id z67mr3198856itc.23.1466885952546; Sat, 25 Jun 2016 13:19:12 -0700 (PDT) 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 MIME-Version: 1.0 Received: by 10.79.34.142 with HTTP; Sat, 25 Jun 2016 13:19:12 -0700 (PDT) In-Reply-To: References: From: Tom H Date: Sat, 25 Jun 2016 16:19:12 -0400 Message-ID: Subject: Re: [gentoo-user] booting - I don't anystand how the (Linux) world works anymore To: Gentoo User Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: f01cc30c-a412-4f41-943e-54351d46ae48 X-Archives-Hash: 0669ef66d5ed8a64f5dbeffe5f5f5a06 On Sat, Jun 25, 2016 at 2:33 PM, Helmut Jarausch wrote: > > I'm a dino since I still use grub-1 but I prefer recent kernels (currently > 4.70-rc4) > > I don't understand the 'root=' option on the boot line like > kernel /boot/vmlinuz-4.7.0-rc4 root=/dev/sda1 > > Here my bad experience: > > Having booted by SystemRescueCD from the cdrom device, my root device is > labelled /dev/sda1 > BUT trying to use that on the kernel boot line fails (the kernel cannot > find the root file system) > > By trial and error I've found that I have to use root=/dev/sdb1 > > but if I plug in an external drive (via USB) this doesn't work any more. > > So, I came up with root=UUID=uuid_number of the root file system. > > But to my surprise I now got a kernel panic > syncing: VFS: unable to mount root fs on unknown block(0,0) > > So, please tell me what I'm missing? Are you using an initramfs? You can't use "root=UUID=uuid" if you don't. You can use "root=PARTUUID=partuuid" where on an msdos-labeled disk: # findmnt / -o TARGET,SOURCE,PARTUUID TARGET SOURCE PARTUUID / /dev/sda1 0006c8d7-01 on a gpt-labeled disk: # findmnt / -o TARGET,SOURCE,PARTUUID TARGET SOURCE PARTUUID / /dev/sda3 41e9268f-484a-43e2-ae81-54d8c84119e0