From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267832AbUG3V0r (ORCPT ); Fri, 30 Jul 2004 17:26:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267848AbUG3V0r (ORCPT ); Fri, 30 Jul 2004 17:26:47 -0400 Received: from host4-67.pool80117.interbusiness.it ([80.117.67.4]:31376 "EHLO dedasys.com") by vger.kernel.org with ESMTP id S267832AbUG3V0m (ORCPT ); Fri, 30 Jul 2004 17:26:42 -0400 To: linux-kernel@vger.kernel.org Subject: [PATCH] speedy boot from usb devices From: davidw@dedasys.com (David N. Welton) Date: 30 Jul 2004 23:25:05 +0200 Message-ID: <87fz79xk5q.fsf@dedasys.com> User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [ Please CC replies to me - thanks! ] Hi, I gather that there isn't much interest in this idea on behalf of the 'mainstream', because initrd is a far more flexible solution, but I happen to like the idea of booting quickly from a USB device, without wasting a bunch of time and space for an initrd, and we're using this in a product as well, so without further ado, I'll point you at http://dedasys.com/freesoftware/patches/ where you can get blkdev_wakeup.patch Works like so: whenever a block device comes on line, it signals this fact to a wait queue, so that the init process can stop and wait for slow devices, in particular things such as USB storage devices, which are much slower than IDE devices. The init process checks the list of available devices and compares it with the desired root device, and if there is a match, proceeds with the initialization process, secure in the knowledge that the device in question has been brought up. This is useful if one wants to boot quickly from a USB storage device without a trimmed-down kernel, and without going through the whole initrd slog. Comments, critiques, suggestions and ideas are all welcome. Thankyou for your time, -- David N. Welton Personal: http://www.dedasys.com/davidw/ Free Software: http://www.dedasys.com/freesoftware/ Apache Tcl: http://tcl.apache.org/ Photos: http://www.dedasys.com/photos/