1 .\" Copyright (c) 1999 Robert Nordier
2 .\" All rights reserved.
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5 .\" modification, are permitted provided that the following conditions
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13 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
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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 1.3 2004/03/11 13:28:58 hmp 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.
83 Verbose: display information about the slices defined, etc.
91 Specify the drive number used by the PC BIOS in referencing the drive
92 which contains the specified
94 Typically this will be 0x80 for the first hard drive, 0x81 for the
95 second hard drive, and so on; however any integer between 0 and 0xff
98 Specify that a backup copy of the preexisting MBR should be written to
100 This file is created if it does not exist, and replaced if it does.
102 Specify slices to be enabled/disabled, where
104 is an integer between 0 (no slices enabled) and 0xf (all four slices
107 A comma-separated string of any of the following options may be
110 prepended as necessary):
111 .Bl -tag -width indent
113 Use the disk packet (BIOS Int 0x13 extensions) interface, as
114 as opposed to the legacy (CHS) interface, when doing disk I/O.
115 This allows booting above cylinder 1023, but requires specific
120 Forces the drive containing the disk to be referenced using drive
121 number definable by means of the -d option.
125 Allow the MBR to be updated by the boot manager.
126 (The MBR may be updated to flag slices as
128 and to save slice selection information.)
129 This is the default; a
131 option causes the MBR to be treated as read-only.
134 Set the default boot selection to
136 Values between 1 and 4 refer to slices; a value of 5 refers to the
137 option of booting from a second disk.
138 This would normally be used in conjunction with the
142 Set the timeout value to
144 (There are approximately 18.2 ticks per second.)
147 .Bl -tag -width /boot/boot0 -compact
154 The following is an example of a typical usage
157 utility to affect the next boot:
159 .Dl "boot0cfg -s 2 ad0"
166 .An Robert Nordier Aq rnordier@FreeBSD.org .
172 to fail, depending on the nature of BIOS support.
176 option with an incorrect -d operand may cause the MBR to be written