Bring in some fixes from FreeBSD.
[dragonfly.git] / usr.sbin / boot0cfg / boot0cfg.8
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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
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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 $
3a3af6af 26.\" $DragonFly: src/usr.sbin/boot0cfg/boot0cfg.8,v 1.4 2008/03/24 23:04:19 swildner Exp $
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3a3af6af 28.Dd March 23, 2008
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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
9bb2a92d 47.Dx
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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.
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82.It Fl b Ar boot0
83Specify which
84.Sq boot0
85image to use.
86The default is
87.Pa /boot/boot0 .
88.It Fl d Ar drive
89Specify the drive number used by the PC BIOS in referencing the drive
90which contains the specified
91.Ar disk .
92Typically this will be 0x80 for the first hard drive, 0x81 for the
93second hard drive, and so on; however any integer between 0 and 0xff
94is acceptable here.
95.It Fl f Ar file
96Specify that a backup copy of the preexisting MBR should be written to
97.Ar file .
98This file is created if it does not exist, and replaced if it does.
99.It Fl m Ar mask
100Specify slices to be enabled/disabled, where
101.Ar mask
102is an integer between 0 (no slices enabled) and 0xf (all four slices
103enabled).
104.It Fl o Ar options
105A comma-separated string of any of the following options may be
106specified (with
107.Dq no
108prepended as necessary):
109.Bl -tag -width indent
110.It packet
3a3af6af 111Use the disk packet (BIOS INT 0x13 extensions) interface,
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112as opposed to the legacy (CHS) interface, when doing disk I/O.
113This allows booting above cylinder 1023, but requires specific
114BIOS support.
115The default is
116.Sq nopacket .
117.It setdrv
118Forces the drive containing the disk to be referenced using drive
119number definable by means of the -d option.
120The default is
121.Sq nosetdrv .
122.It update
123Allow the MBR to be updated by the boot manager.
124(The MBR may be updated to flag slices as
125.Sq active ,
126and to save slice selection information.)
127This is the default; a
128.Sq noupdate
129option causes the MBR to be treated as read-only.
130.El
131.It Fl s Ar slice
132Set the default boot selection to
133.Ar slice .
134Values between 1 and 4 refer to slices; a value of 5 refers to the
135option of booting from a second disk.
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136.It Fl t Ar ticks
137Set the timeout value to
138.Ar ticks .
139(There are approximately 18.2 ticks per second.)
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140.It Fl v
141Verbose: display information about the slices defined, etc.
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142.El
143.Sh FILES
144.Bl -tag -width /boot/boot0 -compact
145.It Pa /boot/boot0
146The default
147.Sq boot0
148image
149.El
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150.Sh EXIT STATUS
151.Ex -std
984263bc 152.Sh EXAMPLES
3a3af6af 153To boot slice 2 on the next boot:
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154.Pp
155.Dl "boot0cfg -s 2 ad0"
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156.Pp
157To enable just slices 1 and 2 in the menu:
158.Pp
159.Dl "boot0cfg -m 0x3 ad0"
160.Pp
161To go back to non-interactive booting, use
162.Xr fdisk 8
163to install the default MBR:
164.Pp
165.Dl "fdisk -B ad0"
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166.Sh SEE ALSO
167.Xr boot 8 ,
168.Xr fdisk 8
169.Sh AUTHORS
170.An Robert Nordier Aq rnordier@FreeBSD.org .
171.Sh BUGS
172Use of the
173.Sq packet
174option may cause
175.Sq boot0
176to fail, depending on the nature of BIOS support.
177.Pp
178Use of the
179.Sq setdrv
180option with an incorrect -d operand may cause the MBR to be written
181to the wrong disk.
182Be careful!