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 which 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, but without 80affecting the embedded slice table. 81.It Fl v 82Verbose: display information about the slices defined, etc. 83.It Fl b Ar boot0 84Specify which 85.Sq boot0 86image to use. 87The default is 88.Pa /boot/boot0 . 89.It Fl d Ar drive 90Specify the drive number used by the PC BIOS in referencing the drive 91which contains the specified 92.Ar disk . 93Typically this will be 0x80 for the first hard drive, 0x81 for the 94second hard drive, and so on; however any integer between 0 and 0xff 95is acceptable here. 96.It Fl f Ar file 97Specify that a backup copy of the preexisting MBR should be written to 98.Ar file . 99This file is created if it does not exist, and truncated if it does. 100.It Fl m Ar mask 101Specify slices to be enabled/disabled, where 102.Ar mask 103is an integer between 0 (no slices enabled) and 0xf (all four slices 104enabled). 105.It Fl o Ar options 106A comma-separated string of any of the following options may be 107specified (with 108.Dq no 109prepended as necessary): 110.Bl -tag -width indent 111.It packet 112Use the disk packet (BIOS Int 0x13 extensions) interface, as 113as opposed to the legacy (CHS) interface, when doing disk I/O. 114This allows booting above cylinder 1023, but requires specific 115BIOS support. 116The default is 117.Sq nopacket . 118.It setdrv 119Forces the drive containing the disk to be referenced using drive 120number definable by means of the -d option. 121The default is 122.Sq nosetdrv . 123.It update 124Allow the MBR to be updated by the boot manager. 125(The MBR may be updated to flag slices as 126.Sq active , 127and to save slice selection information.) 128This is the default; a 129.Sq noupdate 130option causes the MBR to be treated as read-only. 131.El 132.It Fl s Ar slice 133Set the default boot selection to 134.Ar slice . 135Values between 1 and 4 refer to slices; a value of 5 refers to the 136option of booting from a second disk. 137This would normally be used in conjunction with the 138.Sq noupdate 139option. 140.It Fl t Ar ticks 141Set the timeout value to 142.Ar ticks . 143(There are approximately 18.2 ticks per second.) 144.El 145.Sh FILES 146.Bl -tag -width /boot/boot0 -compact 147.It Pa /boot/boot0 148The default 149.Sq boot0 150image 151.El 152.Sh SEE ALSO 153.Xr boot 8 , 154.Xr fdisk 8 155.Sh DIAGNOSTICS 156.Ex -std 157.Sh AUTHORS 158.An Robert Nordier Aq rnordier@FreeBSD.org . 159.Sh BUGS 160Use of the 161.Sq packet 162option may cause 163.Sq boot0 164to fail, depending on the nature of BIOS support. 165.Pp 166Use of the 167.Sq setdrv 168option with an incorrect -d operand may cause the MBR to be written 169to the wrong disk. 170Be careful! 171