1 .\" Copyright (c) 1999 Robert Nordier
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30 .Nd boot manager installation/configuration utility
36 .Op Fl e Ar bell character
48 boot manager permits the operator to select from which disk and
49 slice an i386 machine (PC) is booted.
51 Note that what are referred to here as
57 documentation relating to the PC.
58 Typically, only non-removable disks are sliced.
62 utility optionally installs the
64 boot manager on the specified
66 and allows various operational parameters to be configured.
68 On PCs, a boot manager typically occupies sector 0 of a disk, which is
69 known as the Master Boot Record (MBR).
70 The MBR contains both code (to which control is passed by the PC BIOS)
71 and data (an embedded table of defined slices).
74 .Bl -tag -width indent
79 This option causes MBR code to be replaced, without
80 affecting the embedded slice table.
87 which will use the video card as output, alternatively
89 can be used for output to the COM1 port.
90 (Be aware that nothing will be output to the COM1 port unless the
91 modem signals DSR and CTS are active.)
93 Specify the drive number used by the PC BIOS in referencing the drive
94 which contains the specified
96 Typically this will be 0x80 for the first hard drive, 0x81 for the
97 second hard drive, and so on; however any integer between 0 and 0xff
99 .It Fl e Ar bell character
100 Set the character to be printed in case of input error.
102 Specify that a backup copy of the preexisting MBR should be written to
104 This file is created if it does not exist, and replaced if it does.
105 .It Fl i Ar volume-id
106 Specifies a volume-id (in the form XXXX-XXXX) to be saved at location
107 0x1b8 in the MBR. This information is sometimes used by NT, XP and Vista
108 to identify the disk drive. The option is only compatible with version 2.00
109 of the 512-byte boot block.
111 Specify slices to be enabled/disabled, where
113 is an integer between 0 (no slices enabled) and 0xf (all four slices
115 Each mask bit enables corresponding slice if set to 1.
116 The least significant bit of the mask corresponds to slice 1,
117 the most significant bit of the mask corresponds to slice 4.
119 A comma-separated string of any of the following options may be
122 prepended as necessary):
123 .Bl -tag -width indent
125 Use the disk packet (BIOS INT 0x13 extensions) interface,
126 as opposed to the legacy (CHS) interface, when doing disk I/O.
127 This allows booting above cylinder 1023, but requires specific
132 Forces the drive containing the disk to be referenced using drive
133 number definable by means of the -d option.
137 Allow the MBR to be updated by the boot manager.
138 (The MBR may be updated to flag slices as
140 and to save slice selection information.)
141 This is the default; a
143 option causes the MBR to be treated as read-only.
146 Set the default boot selection to
148 Values between 1 and 4 refer to slices; a value of 5 refers to the
149 option of booting from a second disk.
152 or a value of 6 can be used to boot via PXE.
154 Set the timeout value to
156 (There are approximately 18.2 ticks per second.)
158 Verbose: display information about the slices defined, etc.
161 .Bl -tag -width /boot/boot0sio -compact
166 .It Pa /boot/boot0sio
167 Image for serial consoles (COM1,9600,8,N,1,MODEM)
172 To boot slice 2 on the next boot:
174 .Dl "boot0cfg -s 2 ada0"
176 To enable just slices 1 and 3 in the menu:
178 .Dl "boot0cfg -m 0x5 ada0"
180 To go back to non-interactive booting, use
182 to install the default MBR:
184 .Dl "gpart bootcode -b /boot/mbr ada0"
190 .An Robert Nordier Aq Mt rnordier@FreeBSD.org
196 to fail, depending on the nature of BIOS support.
200 option with an incorrect -d operand may cause the boot0 code
201 to write the MBR to the wrong disk, thus trashing its previous