1 .\" Copyright (c) 1999 Robert Nordier
2 .\" All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
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13 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
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17 .\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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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 $
33 .Nd boot manager installation/configuration utility
49 boot manager permits the operator to select from which disk and
50 slice an i386 machine (PC) is booted.
52 Note that what are referred to here as
58 documentation relating to the PC.
59 Typically, only non-removable disks are sliced.
63 utility optionally installs the
65 boot manager on the specified
67 and allows various operational parameters to be configured.
69 On PCs, a boot manager typically occupies sector 0 of a disk, which is
70 known as the Master Boot Record (MBR).
71 The MBR contains both code (to which control is passed by the PC BIOS)
72 and data (an embedded table of defined slices).
75 .Bl -tag -width indent
80 This option causes MBR code to be replaced, without
81 affecting the embedded slice table.
88 which will use the video card as output, alternatively
90 can be used for output to the COM1 port.
91 (Be aware that nothing will be output to the COM1 port unless the
92 modem signals DSR and CTS are active.)
94 Specify the drive number used by the PC BIOS in referencing the drive
95 which contains the specified
97 Typically this will be 0x80 for the first hard drive, 0x81 for the
98 second hard drive, and so on; however any integer between 0 and 0xff
101 Specify that a backup copy of the preexisting MBR should be written to
103 This file is created if it does not exist, and replaced if it does.
105 Specify slices to be enabled/disabled, where
107 is an integer between 0 (no slices enabled) and 0xf (all four slices
110 A comma-separated string of any of the following options may be
113 prepended as necessary):
114 .Bl -tag -width indent
116 Try to use the disk packet (BIOS INT 0x13 extensions) interface,
117 as opposed to the legacy (CHS) interface, when doing disk I/O.
118 It might be necessary to avoid packet mode for very old systems,
119 which have broken packet mode support.
123 Forces the drive containing the disk to be referenced using drive
124 number definable by means of the
130 Allow the MBR to be updated by the boot manager.
131 (The MBR may be updated to flag slices as
133 and to save slice selection information.)
134 This is the default; a
136 option causes the MBR to be treated as read-only.
139 Set the default boot selection to
141 Values between 1 and 4 refer to slices; a value of 5 refers to the
142 option of booting from a second disk.
144 Set the timeout value to
146 (There are approximately 18.2 ticks per second.)
148 Verbose: display information about the slices defined, etc.
151 .Bl -tag -width ".Pa /boot/boot0sio" -compact
156 .It Pa /boot/boot0sio
157 Image for serial consoles (COM1,9600,8,N,1,MODEM)
162 To boot slice 2 on the next boot:
164 .Dl "boot0cfg -s 2 ad0"
166 To enable just slices 1 and 2 in the menu:
168 .Dl "boot0cfg -m 0x3 ad0"
170 To go back to non-interactive booting, use
172 to install the default MBR:
179 .An Robert Nordier Aq rnordier@FreeBSD.org .
185 to fail, depending on the nature of BIOS support.
189 option with an incorrect
191 operand may cause the MBR to be written to the wrong disk.