1.\" Copyright (c) 1999 Robert Nordier 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 17.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 18.\" OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 19.\" OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 20.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 21.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 22.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 23.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24.\" 25.\" $FreeBSD: src/usr.sbin/boot0cfg/boot0cfg.8,v 1.5.2.6 2003/03/12 22:08:13 trhodes Exp $ 26.\" $DragonFly: src/usr.sbin/boot0cfg/boot0cfg.8,v 1.4 2008/03/24 23:04:19 swildner Exp $ 27.\" 28.Dd June 20, 2009 29.Dt BOOT0CFG 8 30.Os 31.Sh NAME 32.Nm boot0cfg 33.Nd boot manager installation/configuration utility 34.Sh SYNOPSIS 35.Nm 36.Op Fl Bv 37.Op Fl b Ar boot0 38.Op Fl d Ar drive 39.Op Fl f Ar file 40.Op Fl m Ar mask 41.Op Fl o Ar options 42.Op Fl s Ar slice 43.Op Fl t Ar ticks 44.Ar disk 45.Sh DESCRIPTION 46The 47.Dx 48.Sq boot0 49boot manager permits the operator to select from which disk and 50slice an i386 machine (PC) is booted. 51.Pp 52Note that what are referred to here as 53.Dq slices 54are typically called 55.Dq partitions 56in 57.No non- Ns Bx 58documentation relating to the PC. 59Typically, only non-removable disks are sliced. 60.Pp 61The 62.Nm 63utility optionally installs the 64.Sq boot0 65boot manager on the specified 66.Ar disk ; 67and allows various operational parameters to be configured. 68.Pp 69On PCs, a boot manager typically occupies sector 0 of a disk, which is 70known as the Master Boot Record (MBR). 71The MBR contains both code (to which control is passed by the PC BIOS) 72and data (an embedded table of defined slices). 73.Pp 74The options are: 75.Bl -tag -width indent 76.It Fl B 77Install the 78.Sq boot0 79boot manager. 80This option causes MBR code to be replaced, without 81affecting the embedded slice table. 82.It Fl b Ar boot0 83Specify which 84.Sq boot0 85image to use. 86The default is 87.Pa /boot/boot0 88which will use the video card as output, alternatively 89.Pa /boot/boot0sio 90can be used for output to the COM1 port. 91(Be aware that nothing will be output to the COM1 port unless the 92modem signals DSR and CTS are active.) 93.It Fl d Ar drive 94Specify the drive number used by the PC BIOS in referencing the drive 95which contains the specified 96.Ar disk . 97Typically this will be 0x80 for the first hard drive, 0x81 for the 98second hard drive, and so on; however any integer between 0 and 0xff 99is acceptable here. 100.It Fl f Ar file 101Specify that a backup copy of the preexisting MBR should be written to 102.Ar file . 103This file is created if it does not exist, and replaced if it does. 104.It Fl m Ar mask 105Specify slices to be enabled/disabled, where 106.Ar mask 107is an integer between 0 (no slices enabled) and 0xf (all four slices 108enabled). 109.It Fl o Ar options 110A comma-separated string of any of the following options may be 111specified (with 112.Dq no 113prepended as necessary): 114.Bl -tag -width indent 115.It packet 116Try to use the disk packet (BIOS INT 0x13 extensions) interface, 117as opposed to the legacy (CHS) interface, when doing disk I/O. 118It might be necessary to avoid packet mode for very old systems, 119which have broken packet mode support. 120The default is 121.Sq packet . 122.It setdrv 123Forces the drive containing the disk to be referenced using drive 124number definable by means of the 125.Fl d 126option. 127The default is 128.Sq nosetdrv . 129.It update 130Allow the MBR to be updated by the boot manager. 131(The MBR may be updated to flag slices as 132.Sq active , 133and to save slice selection information.) 134This is the default; a 135.Sq noupdate 136option causes the MBR to be treated as read-only. 137.El 138.It Fl s Ar slice 139Set the default boot selection to 140.Ar slice . 141Values between 1 and 4 refer to slices; a value of 5 refers to the 142option of booting from a second disk. 143.It Fl t Ar ticks 144Set the timeout value to 145.Ar ticks . 146(There are approximately 18.2 ticks per second.) 147.It Fl v 148Verbose: display information about the slices defined, etc. 149.El 150.Sh FILES 151.Bl -tag -width ".Pa /boot/boot0sio" -compact 152.It Pa /boot/boot0 153The default 154.Sq boot0 155image 156.It Pa /boot/boot0sio 157Image for serial consoles (COM1,9600,8,N,1,MODEM) 158.El 159.Sh EXIT STATUS 160.Ex -std 161.Sh EXAMPLES 162To boot slice 2 on the next boot: 163.Pp 164.Dl "boot0cfg -s 2 ad0" 165.Pp 166To enable just slices 1 and 2 in the menu: 167.Pp 168.Dl "boot0cfg -m 0x3 ad0" 169.Pp 170To go back to non-interactive booting, use 171.Xr fdisk 8 172to install the default MBR: 173.Pp 174.Dl "fdisk -B ad0" 175.Sh SEE ALSO 176.Xr boot 8 , 177.Xr fdisk 8 178.Sh AUTHORS 179.An Robert Nordier Aq rnordier@FreeBSD.org . 180.Sh BUGS 181Use of the 182.Sq packet 183option may cause 184.Sq boot0 185to fail, depending on the nature of BIOS support. 186.Pp 187Use of the 188.Sq setdrv 189option with an incorrect 190.Fl d 191operand may cause the MBR to be written to the wrong disk. 192Be careful! 193