1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software written and contributed 5.\" to Berkeley by William Jolitz. 6.\" 7.\" Almost completely rewritten for FreeBSD 2.1 by Joerg Wunsch. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the University of 20.\" California, Berkeley and its contributors. 21.\" 4. Neither the name of the University nor the names of its contributors 22.\" may be used to endorse or promote products derived from this software 23.\" without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" @(#)boot_i386.8 8.2 (Berkeley) 4/19/94 38.\" 39.\" $Id$ 40.\" 41.Dd April 19, 1994 42.Dt BOOT 8 i386 43.Os 44.Sh NAME 45.Nm boot 46.Nd 47system bootstrapping procedures 48.Sh DESCRIPTION 49.Sy Power fail and crash recovery. 50Normally, the system will reboot itself at power-up or after crashes. 51An automatic consistency check of the file systems will be performed, 52and unless this fails, the system will resume multi-user operations. 53.Pp 54.Sy Cold starts. 55Most 386 56.Tn "PC AT" 57clones attempt to boot the floppy disk drive 0 (otherwise known as 58drive A:) first, and failing that, attempt to boot the hard disk 59controller 1, drive 0 (otherwise known as drive C:, or drive 0x80 in 60the BIOS). The automatic boot will attempt to load 61.Pa /kernel 62from partition 63.Ql a 64of either the floppy or the hard disk. 65This boot may be aborted by typing any character on the keyboard 66at the 67.Ql Boot: 68prompt. At this time, the following input will be accepted: 69.Bl -tag -offset indent -width 10x 70.It \&? 71Give a short listing of the files in the root directory of the default 72boot device, as a hint about available boot files. 73.It Op ctrlr(unit,part) Op /filename Op Fl abcCdhrsv 74Specify boot file and flags. 75.Bl -tag -offset indent -width 10x -compact 76.It ctrlr 77The controller to boot from. Note that the controller is required 78to have BIOS support since the BIOS services are used to load the 79boot file image. 80.Pp 81Common controller names are: 82.Bl -tag -offset indent -width "wdXX" -compact 83.It wd 84ST506, IDE, ESDI, RLL disks on a WD100[2367] or lookalike 85controller 86.It fd 875 1/4" or 3 1/2" High density floppies 88.It sd 89SCSI disk on any supported SCSI controller 90.It cd 91boot from CDROM 92.It hd 93Pseudo-controller, must be used to specify that unit number 941 (known to the BIOS as drive 0x81) is on a different controller 95than unit number 0. This can happen for the wd vs. sd case. 96.El 97.It unit 98The unit number of the drive on the controller being used. Either 0 99or 1 for the wd and fd and most sd controllers, between 0 and 6 for 100some newer sd controllers. 101.It part 102The partition letter inside the BSD portion of the disk. See 103.Xr disklabel 8 . 104By convention, only partition 105.Ql a 106contains a bootable image. If sliced disks are used 107.Pq Dq fdisk partitions , 108only the first BSD slice can be used to boot from. The partition 109letter does always refer to this slice then. 110.It /filename 111The pathname of the file to boot; must be inside the root directory 112of the specified partition. Defaults to 113.Pa /kernel . 114Symbolic links are not supported (hard links are). 115.It Fl abcCdhrsv 116Boot flags: 117.Bl -tag -offset indent -width "-CXX" -compact 118.It Fl a 119ask for the device to install as root file system during kernel 120initialization 121.It Fl b 122do not automatically reboot after shutdown or crash 123.It Fl c 124run UserConfig to modify hardware parameters for the loaded 125kernel 126.It Fl C 127boot from CDROM 128.It Fl d 129enter the DDB kernel debugger 130.Pq see Xr ddb 4 131before configuring any device (except the system's console) 132.It Fl h 133toggle serial/graphics console 134.It Fl r 135do not establish the root directory of the file system 136hierarchy on the device where the boot file is being loaded 137from 138.It Fl s 139boot into single-user mode; if the console is marked as 140.Dq insecure 141.Pq see Xr ttys 5 , 142the root password must be entered 143.It Fl v 144be verbose during device probing 145.El 146.El 147.El 148.Sh FILES 149.Bl -tag -width /kernelxx -compact 150.It Pa /kernel 151system code 152.\" .It Pa /boot 153.\" system bootstrap 154.El 155.Sh SEE ALSO 156.Xr ddb 4 , 157.Xr ttys 5 , 158.Xr disklabel 8 , 159.Xr halt 8 , 160.Xr reboot 8 , 161.Xr shutdown 8 162.Sh BUGS 163The disklabel format used by this version of 164.Bx 165is quite 166different from that of other architectures. 167.Pp 168The boot flags are not very self-explanatory, and the alphabet has 169too few characters to implement every potentially useful boot option. 170