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 1.3 2004/03/11 12:28:58 hmp Exp $ 27.\" 28.Dd February 21, 1999 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 v 83Verbose: display information about the slices defined, etc. 84.It Fl b Ar boot0 85Specify which 86.Sq boot0 87image to use. 88The default is 89.Pa /boot/boot0 . 90.It Fl d Ar drive 91Specify the drive number used by the PC BIOS in referencing the drive 92which contains the specified 93.Ar disk . 94Typically this will be 0x80 for the first hard drive, 0x81 for the 95second hard drive, and so on; however any integer between 0 and 0xff 96is acceptable here. 97.It Fl f Ar file 98Specify that a backup copy of the preexisting MBR should be written to 99.Ar file . 100This file is created if it does not exist, and replaced if it does. 101.It Fl m Ar mask 102Specify slices to be enabled/disabled, where 103.Ar mask 104is an integer between 0 (no slices enabled) and 0xf (all four slices 105enabled). 106.It Fl o Ar options 107A comma-separated string of any of the following options may be 108specified (with 109.Dq no 110prepended as necessary): 111.Bl -tag -width indent 112.It packet 113Use the disk packet (BIOS Int 0x13 extensions) interface, as 114as opposed to the legacy (CHS) interface, when doing disk I/O. 115This allows booting above cylinder 1023, but requires specific 116BIOS support. 117The default is 118.Sq nopacket . 119.It setdrv 120Forces the drive containing the disk to be referenced using drive 121number definable by means of the -d option. 122The default is 123.Sq nosetdrv . 124.It update 125Allow the MBR to be updated by the boot manager. 126(The MBR may be updated to flag slices as 127.Sq active , 128and to save slice selection information.) 129This is the default; a 130.Sq noupdate 131option causes the MBR to be treated as read-only. 132.El 133.It Fl s Ar slice 134Set the default boot selection to 135.Ar slice . 136Values between 1 and 4 refer to slices; a value of 5 refers to the 137option of booting from a second disk. 138This would normally be used in conjunction with the 139.Sq noupdate 140option. 141.It Fl t Ar ticks 142Set the timeout value to 143.Ar ticks . 144(There are approximately 18.2 ticks per second.) 145.El 146.Sh FILES 147.Bl -tag -width /boot/boot0 -compact 148.It Pa /boot/boot0 149The default 150.Sq boot0 151image 152.El 153.Sh EXAMPLES 154The following is an example of a typical usage 155of the 156.Nm 157utility to affect the next boot: 158.Pp 159.Dl "boot0cfg -s 2 ad0" 160.Sh DIAGNOSTICS 161.Ex -std 162.Sh SEE ALSO 163.Xr boot 8 , 164.Xr fdisk 8 165.Sh AUTHORS 166.An Robert Nordier Aq rnordier@FreeBSD.org . 167.Sh BUGS 168Use of the 169.Sq packet 170option may cause 171.Sq boot0 172to fail, depending on the nature of BIOS support. 173.Pp 174Use of the 175.Sq setdrv 176option with an incorrect -d operand may cause the MBR to be written 177to the wrong disk. 178Be careful! 179