1.\" $NetBSD: multiboot.8,v 1.1 2013/07/31 21:01:13 soren Exp $ 2.\" 3.\" Copyright (c) 2006 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Julio M. Merino Vidal. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd October 25, 2006 31.Dt MULTIBOOT 8 x86 32.Os 33.Sh NAME 34.Nm multiboot 35.Nd procedure for booting NetBSD/x86 from a Multiboot-compliant boot loader 36.Sh DESCRIPTION 37Multiboot is a specification that defines a protocol between a boot loader 38and a kernel. 39This protocol allows passing boot information between the two in a standard 40way, allowing any Multiboot-compliant boot loader to boot any 41Multiboot-compliant kernel. 42The 43.Nx 44kernel supports Multiboot if it was compiled with 45.Cd options MULTIBOOT 46(the default in the 47.Sq GENERIC 48and 49.Sq GENERIC_LAPTOP 50configurations). 51.Pp 52Unlike when using the native boot loader, the 53.Nx 54kernel recognizes a set of command line arguments if booted through a 55Multiboot-compliant boot loader. 56This is because the Multiboot protocol is not complete enough to completely 57configure a 58.Nx 59kernel. 60.Pp 61The following arguments are recognized: 62.Bl -tag -width consoleXspeedX 63.It Va console 64Specifies the console device name. 65Can be one of 66.Sq com 67or 68.Sq pc . 69If the former, 70.Va console_addr 71and 72.Va console_speed 73should be given too. 74.It Va console_addr 75Specifies the serial port address for the console. 76Defaults to the value of 77.Cd options CONADDR 78or 79.Sq 0x3f8 80if this was not given. 81.It Va console_speed 82Specifies the serial port speed for the console. 83Defaults to the value of 84.Cd options CONSPEED 85or 86.Sq 9600 87if this was not given. 88.It Va root 89Specifies the name of the device to be mounted as the root partition. 90It should not be needed because the kernel tries its best to guess which 91is the root partition (basing the decision on the device from which the 92kernel was loaded from). 93In cases where the automatic detection fails, this flag comes useful. 94Example: 95.Sq root=wd0e . 96.El 97.Ss Booting with GRUB Legacy 98GRUB Legacy is the most popular bootloader that supports Multiboot. 99You can boot a 100.Nx 101kernel (assuming it is compiled with Multiboot support) with a line 102similar to the following one: 103.Bd -literal 104kernel (fd0)/netbsd.gz -c console=pc root=wd0e 105.Ed 106.Sh SEE ALSO 107.Xr options 4 108.Sh HISTORY 109.Nm 110support first appeared in 111.Nx 4.0 . 112.Sh AUTHORS 113.Nm 114support was added by 115.An Julio M. Merino Vidal Aq Mt jmmv@NetBSD.org . 116