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.\" $FreeBSD$ 26.\" 27.Dd February 21, 1999 28.Dt BOOT0CFG 8 29.Os 30.Sh NAME 31.Nm boot0cfg 32.Nd boot manager installation/configuration utility 33.Sh SYNOPSIS 34.Nm 35.Op Fl Bv 36.Op Fl b Ar boot0 37.Op Fl d Ar drive 38.Op Fl f Ar file 39.Op Fl m Ar mask 40.Op Fl o Ar options 41.Op Fl s Ar slice 42.Op Fl t Ar ticks 43.Ar disk 44.Sh DESCRIPTION 45The 46.Fx 47.Sq boot0 48boot manager permits the operator to select from which disk and 49slice an i386 machine (PC) is booted. 50.Pp 51Note that what are referred to here as 52.Dq slices 53are typically called 54.Dq partitions 55in 56.No non- Ns Bx 57documentation relating to the PC. 58Typically, only non-removable disks are sliced. 59.Pp 60The 61.Nm 62utility optionally installs the 63.Sq boot0 64boot manager on the specified 65.Ar disk ; 66and allows various operational parameters to be configured. 67.Pp 68On PCs, a boot manager typically occupies sector 0 of a disk, which is 69known as the Master Boot Record (MBR). 70The MBR contains both code (to which control is passed by the PC BIOS) 71and data (an embedded table of defined slices). 72.Pp 73The options are: 74.Bl -tag -width indent 75.It Fl B 76Install the 77.Sq boot0 78boot manager. 79This option causes MBR code to be replaced, without 80affecting the embedded slice table. 81.It Fl b Ar boot0 82Specify which 83.Sq boot0 84image to use. 85The default is 86.Pa /boot/boot0 . 87.It Fl d Ar drive 88Specify the drive number used by the PC BIOS in referencing the drive 89which contains the specified 90.Ar disk . 91Typically this will be 0x80 for the first hard drive, 0x81 for the 92second hard drive, and so on; however any integer between 0 and 0xff 93is acceptable here. 94.It Fl f Ar file 95Specify that a backup copy of the preexisting MBR should be written to 96.Ar file . 97This file is created if it does not exist, and replaced if it does. 98.It Fl m Ar mask 99Specify slices to be enabled/disabled, where 100.Ar mask 101is an integer between 0 (no slices enabled) and 0xf (all four slices 102enabled). 103.It Fl o Ar options 104A comma-separated string of any of the following options may be 105specified (with 106.Dq no 107prepended as necessary): 108.Bl -tag -width indent 109.It packet 110Use the disk packet (BIOS Int 0x13 extensions) interface, as 111as opposed to the legacy (CHS) interface, when doing disk I/O. 112This allows booting above cylinder 1023, but requires specific 113BIOS support. 114The default is 115.Sq nopacket . 116.It setdrv 117Forces the drive containing the disk to be referenced using drive 118number definable by means of the -d option. 119The default is 120.Sq nosetdrv . 121.It update 122Allow the MBR to be updated by the boot manager. 123(The MBR may be updated to flag slices as 124.Sq active , 125and to save slice selection information.) 126This is the default; a 127.Sq noupdate 128option causes the MBR to be treated as read-only. 129.El 130.It Fl s Ar slice 131Set the default boot selection to 132.Ar slice . 133Values between 1 and 4 refer to slices; a value of 5 refers to the 134option of booting from a second disk. 135.It Fl t Ar ticks 136Set the timeout value to 137.Ar ticks . 138(There are approximately 18.2 ticks per second.) 139.It Fl v 140Verbose: display information about the slices defined, etc. 141.El 142.Sh FILES 143.Bl -tag -width /boot/boot0 -compact 144.It Pa /boot/boot0 145The default 146.Sq boot0 147image 148.El 149.Sh EXAMPLES 150The following is an example of a typical usage 151of the 152.Nm 153command to affect the next boot: 154.Pp 155.Dl "boot0cfg -s 2 ad0" 156.Sh DIAGNOSTICS 157.Ex -std 158.Sh SEE ALSO 159.Xr boot 8 , 160.Xr fdisk 8 161.Sh AUTHORS 162.An Robert Nordier Aq rnordier@FreeBSD.org . 163.Sh BUGS 164Use of the 165.Sq packet 166option may cause 167.Sq boot0 168to fail, depending on the nature of BIOS support. 169.Pp 170Use of the 171.Sq setdrv 172option with an incorrect -d operand may cause the MBR to be written 173to the wrong disk. 174Be careful! 175