652 lines
15 KiB
Groff
652 lines
15 KiB
Groff
.\" $NetBSD: boot.8,v 1.58 2011/05/31 03:43:47 uebayasi Exp $
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.\"
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.\" Copyright (c) 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software written and contributed
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.\" to Berkeley by William Jolitz.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)boot_i386.8 8.2 (Berkeley) 4/19/94
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.\"
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.Dd May 26, 2011
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.Dt BOOT 8 i386
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.Os
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.Sh NAME
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.Nm boot
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.Nd
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system bootstrapping procedures
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.Sh DESCRIPTION
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.Tn IA-32
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computers
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.Po
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the
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.Tn IBM PC
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and its clones
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.Pc
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that can run
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.Nx Ns /i386
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can use any of the following boot procedures, depending on what the hardware and
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.Tn BIOS
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support:
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.Pp
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.Bl -tag -width "pxeboot(8)"
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.It boot
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bootstrap
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.Nx
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from the system
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.Tn BIOS
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.It Xr dosboot 8
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bootstrap
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.Nx
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from
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.Tn MS-DOS
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.It Xr w95boot 8
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bootstrap
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.Nx
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from
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.Tn Windows 95
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.It Xr pxeboot 8
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network bootstrap
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.Nx
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from a
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.Tn TCP/IP
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.Tn LAN
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with
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.Tn DHCP ,
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.Tn TFTP ,
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and
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.Tn NFS .
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.El
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.Ss Power fail and crash recovery
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Normally, the system will reboot itself at power-up or after crashes.
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An automatic consistency check of the file systems will be performed,
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and unless this fails, the system will resume multi-user operations.
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.Ss Cold starts
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The 386
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.Tn "PC AT"
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clones attempt to boot the floppy disk drive A (otherwise known as drive
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0) first, and failing that, attempt to boot the hard disk C (otherwise
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known as hard disk controller 1, drive 0).
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The
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.Nx
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bootblocks are loaded and started either by the
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.Tn BIOS ,
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or by a boot selector program (such as OS-BS, BOOTEASY, the OS/2 Boot Menu or
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.Nx Ns 's
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.No boot-selecting
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master boot record - see
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.Xr mbr 8 ) .
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.Ss Normal Operation
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Once running, a banner similar to the following will appear:
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.Bd -unfilled -offset indent
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\*[Gt]\*[Gt] NetBSD BIOS Boot, revision 3.0
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\*[Gt]\*[Gt] (user@buildhost, builddate)
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\*[Gt]\*[Gt] Memory: 637/15360 k
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Press return to boot now, any other key for boot menu
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booting hd0a:netbsd - starting in 5
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.Ed
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.Pp
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After a countdown, the system image listed will be loaded.
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In the example above, it will be
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.Dq Li hd0a:netbsd
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which is the file
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.Nm netbsd
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on partition
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.Dq a
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of the
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.Nx
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.Tn MBR
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partition of the first hard disk known to the
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.Tn BIOS
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.Po
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which is an
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.Tn IDE
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or similar device - see the
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.Sx BUGS
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section
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.Pc .
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.Pp
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Pressing a key within the time limit, or before the boot program starts, will
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enter interactive mode.
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When using a short or 0 timeout, it is often useful to interrupt the boot
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by holding down a shift key, as some BIOSes and BIOS extensions will drain the
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keystroke buffer at various points during POST.
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.Pp
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If present, the file
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.Pa /boot.cfg
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will be used to configure the behaviour of the boot loader including
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setting the timeout, choosing a console device, altering the banner
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text and displaying a menu allowing boot commands to be easily chosen.
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See
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.Xr boot.cfg 5 .
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.Pp
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The
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.Nx Ns /i386
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boot loader can boot a kernel using either the native
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.Nx
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boot protocol, or the
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.Dq multiboot
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protocol (which is compatible with some other operating systems).
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In the native
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.Nx
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boot protocol, options are passed from the boot loader
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to the kernel via flag bits in the
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.Va boothowto
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variable (see
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.Xr boothowto 9 ) .
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In the multiboot protocol, options are passed from the boot loader
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to the kernel as strings.
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.Ss Diagnostic Output
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If the first stage boot fails to load the boot, it will print a terse
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message indicating the reason for the failure.
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The possible error messages and their cause are listed in
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.Xr mbr 8 .
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.Pp
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If the first stage boot succeeds, the banner will be shown and the
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error messages should be self-explanatory.
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.Ss Interactive mode
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In interactive mode, the boot loader will present a prompt, allowing
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input of these commands:
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.\" NOTE: much of this text is duplicated in the MI boot.8.
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.\" Some of it is
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.\" also duplicated in the i386-specific dosboot.8 and pxeboot.8;
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.\" please try to keep all relevant files synchronized.
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.Bl -tag -width 04n -offset 04n
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.It Ic boot Oo Va device : Ns Oc Oo Va filename Oc Oo Fl 1234abcdmqsvxz Oc
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The default
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.Va device
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will be set to the disk that the boot loader was
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loaded from.
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To boot from an alternate disk, the full name of the device should
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be given at the prompt.
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.Va device
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is of the form
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.Xo Va xd
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.Op Va N Ns Op Va x
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.Xc
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where
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.Va xd
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is the device from which to boot,
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.Va N
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is the unit number, and
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.Va x
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is the partition letter.
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.Pp
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The following list of supported devices may vary from installation to
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installation:
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.Pp
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.Bl -hang -compact
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.It hd
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Hard disks as numbered by the BIOS.
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This includes ST506, IDE, ESDI, RLL disks on a WD100[2367] or
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lookalike controller(s), and SCSI disks
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on SCSI controllers recognized by the BIOS.
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.It fd
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Floppy drives as numbered by the BIOS.
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.El
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.Pp
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The default
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.Va filename
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is
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.Pa netbsd ;
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if the boot loader fails to successfully
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open that image, it then tries
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.Pa netbsd.gz
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(expected to be a kernel image compressed by gzip), followed by
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.Pa netbsd.old ,
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.Pa netbsd.old.gz ,
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.Pa onetbsd ,
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and finally
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.Pa onetbsd.gz .
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Alternate system images can be loaded by just specifying the name of the image.
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.Pp
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Options are:
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.Bl -tag -width xxx
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.It Fl 1
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Sets the machine-dependent flag
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.Sy RB_MD1
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in
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.Va boothowto .
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In
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.Nx Ns /i386 ,
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this disables multiprocessor boot;
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the kernel will boot in uniprocessor mode.
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.It Fl 2
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Sets the machine-dependent flag
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.Sy RB_MD2
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in
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.Va boothowto .
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In
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.Nx Ns /i386 ,
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this disables ACPI.
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.It Fl 3
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Sets the machine-dependent flag
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.Sy RB_MD3
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in
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.Va boothowto .
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In
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.Nx Ns /i386 ,
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this has no effect.
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.It Fl 4
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Sets the machine-dependent flag
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.Sy RB_MD4
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in
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.Va boothowto .
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In
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.Nx Ns /i386 ,
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this has no effect.
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.It Fl a
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Sets the
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.Sy RB_ASKNAME
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flag in
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.Va boothowto .
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This causes the kernel to prompt for the root file system device,
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the system crash dump device, and the path to
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.Xr init 8 .
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.It Fl b
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Sets the
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.Sy RB_HALT
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flag in
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.Va boothowto .
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This causes subsequent reboot attempts to halt instead of rebooting.
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.It Fl c
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Sets the
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.Sy RB_USERCONF
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flag in
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.Va boothowto .
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This causes the kernel to enter the
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.Xr userconf 4
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device configuration manager as soon as possible during the boot.
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.Xr userconf 4
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allows devices to be enabled or disabled, and allows device locators
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(such as hardware addresses or bus numbers)
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to be modified before the kernel attempts to attach the devices.
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.It Fl d
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Sets the
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.Sy RB_KDB
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flag in
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.Va boothowto .
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Requests the kernel to enter debug mode, in which it
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waits for a connection from a kernel debugger; see
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.Xr ddb 4 .
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.It Fl m
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Sets the
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.Sy RB_MINIROOT
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flag in
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.Va boothowto .
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Informs the kernel that a mini-root file system is present in memory.
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.It Fl q
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Sets the
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.Sy AB_QUIET
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flag in
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.Va boothowto .
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Boot the system in quiet mode.
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.It Fl s
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Sets the
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.Sy RB_SINGLE
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flag in
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.Va boothowto .
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Boot the system in single-user mode.
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.It Fl v
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Sets the
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.Sy AB_VERBOSE
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flag in
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.Va boothowto .
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Boot the system in verbose mode.
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.It Fl x
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Sets the
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.Sy AB_DEBUG
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flag in
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.Va boothowto .
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Boot the system with debug messages enabled.
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.It Fl z
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Sets the
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.Sy AB_SILENT
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flag in
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.Va boothowto .
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Boot the system in silent mode.
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.El
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.It Ic consdev Va dev
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Immediately switch the console to the specified device
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.Va dev
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and reprint the banner.
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.Va dev
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must be one of
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.\" .Bl -item -width com[0123]kbd -offset indent -compact
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.Ar pc , com0 , com1 , com2 ,
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.Ar com3 , com0kbd , com1kbd , com2kbd ,
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.Ar com3kbd ,
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or
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.Ar auto .
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See
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.Sx Console Selection Policy
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in
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.Xr boot_console 8 .
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.It Ic dev Op Va device
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Set the default drive and partition for subsequent filesystem
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operations.
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Without an argument, print the current setting.
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.Va device
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is of the form specified in
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.Cm boot .
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.It Ic help
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Print an overview about commands and arguments.
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.It Ic load Va module Op Ar arguments
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Load the specified kernel
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.Va module ,
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and pass it the specified
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.Ar arguments .
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If the module name is not an absolute path,
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.Pa /stand/ Xo Ns
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.Aq Sy arch Ns
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.Pa / Ns
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.Aq Sy osversion Ns
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.Pa /modules/ Ns
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.Aq Sy module Ns
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.Pa / Ns
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.Aq Sy module Ns
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.Pa .kmod
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.Xc
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is used.
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Possible used of the
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.Ic load
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command include loading a memory disk image before booting a kernel,
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or loading a
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.Tn Xen
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DOM0 kernel before booting the
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.Tn Xen
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hypervisor.
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See
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.Xr boot.cfg 5
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for examples.
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.Pp
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In addition to the
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.Cm boot
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options specified above, the DOM0 kernel accepts
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.Po Ar arguments
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being separated with spaces
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.Pc :
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.Bl -tag -width xxx
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.It Ic bootdev Ns = Ns Ar dev Po or Ic root Ns = Ns Ar dev Pc
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Override the default boot device.
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.Ar dev
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can be a unit name
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.Po Dq wd0
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.Pc ,
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or an interface name
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.Po Dq bge0 ,
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.Dq wm0 ,
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.Ns ...
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.Pc ,
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for cases where the root file system has to be loaded
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from network (see the
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.Sx BUGS
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section in
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.Xr pxeboot 8 ) .
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.It Ic console Ns = Ns Ar dev
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Console used by DOM0 kernel during boot.
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.Ar dev
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accepts the same values as the ones given for the
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.Cm consdev
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command.
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See
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.Sx Console Selection Policy
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in
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.Xr boot_console 8 .
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.It Xo Ic ip Ns = Ns
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.Ar my_ip Ns : Ns Ar serv_ip Ns : Ns Ar gw_ip Ns : Ns
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.Ar mask Ns : Ns Ar host Ns : Ns Ar iface
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.Xc
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Specify various parameters for a network boot (IPs are in
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dot notation),
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each one separated by a colon:
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.Bl -tag -width xxxxxxx
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.It Va my_ip
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address of the host
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.It Va serv_ip
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address of the NFS server
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.It Va gw_ip
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address of the gateway
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.It Va mask
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network mask
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.It Va host
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address of the host
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.It Va iface
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interface
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.Po e.g. Dq xennet0
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or
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.Dq eth0
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.Pc
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.El
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.It Ic nfsroot Ns = Ns Ar address Ns : Ns Ar rootpath
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Boot the system with root on NFS.
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.Ar address
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is the address of the NFS server, and
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.Ar rootpath
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is the remote mount point for the root file system.
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.It Ic pciback.hide Ns = Ns Ar pcidevs
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Pass a list of PCI IDs for use with the PCI backend driver,
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.Xr pciback 4 .
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.Ar pcidevs
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is formed of multiple IDs (in bus:device.function notation),
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each ID being surrounded with brackets.
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PCI domain IDs are currently ignored.
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See
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.Xr pciback 4 .
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.El
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.It Ic load_mods Va mods_path_pattern
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Load modules specified by pattern like /some_path/mod*.
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.It Ic ls Op Pa path
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Print a directory listing of
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.Pa path ,
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containing inode number, filename, and file type.
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.Pa path
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can contain a device specification.
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.It Ic modules Bro Ar on | off | enabled | disabled Brc
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The values
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.Ar enabled , on
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will enable module loading for
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.Cm boot
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and
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.Cm multiboot ,
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whereas
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.Ar disabled , off
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will turn off the feature.
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.It Ic multiboot Va kernel Op Ar arguments
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Boot the specified
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.Va kernel ,
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using the
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.Dq multiboot
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protocol instead of the native
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.Nx
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boot protocol.
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The
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.Va kernel
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is specified in the same way as with the
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.Ic boot
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command.
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.Pp
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The multiboot protocol may be used in the following cases:
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.Bl -tag -width indent
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.It Nx Ns / Ns Xen No kernels
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The
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.Tn Xen
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DOM0 kernel must be loaded as a module using the
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.Ic load
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command, and the
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.Tn Xen
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hypervisor must be booted using the
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.Ic multiboot
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command.
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Options for the DOM0 kernel (such as
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.Dq -s
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for single user mode) must be passed as options to the
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.Ic load
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command.
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|
Options for the hypervisor (such as
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.Dq dom0_mem=256M
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to reserve 256 MB of memory for DOM0)
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must be passed as options to the
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.Ic multiboot
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command.
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|
See
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.Xr boot.cfg 5
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for examples on how to boot
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.Nx Ns / Ns Xen.
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.It Nx No multiboot kernels
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A
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.Nx
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kernel that was built with
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.Cd options MULTIBOOT
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(see
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.Xr multiboot 8 )
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|
may be booted with either the
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.Ic boot
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or
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.Ic multiboot
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command, passing the same
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.Ar arguments
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in either case.
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.It Non- Ns Nx No kernels
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A kernel for a
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.No non- Ns Nx
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operating system that expects to be booted using the
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multiboot protocol (such as by the GNU
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.Dq GRUB
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boot loader)
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may be booted using the
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.Ic multiboot
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command.
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|
See the foreign operating system's documentation for the available
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.Ar arguments .
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.El
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.It Ic quit
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|
Reboot the system.
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.It Ic userconf Va command
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Pass the
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.Va command
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to
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.Xr userconf 4
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at boot time .
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|
These commands are processed before the interactive
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.Xr userconf 4
|
|
shell is executed, if requested .
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.It Ic vesa Bro Va modenum | Ar on | off | enabled | disabled | list Brc
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|
Initialise the video card to the specified resolution and bit depth.
|
|
The
|
|
.Va modenum
|
|
should be in the form of
|
|
.Ar 0x100 , 800x600 , 800x600x32 .
|
|
The values
|
|
.Ar enabled , on
|
|
put the display into the default mode, and
|
|
.Ar disabled , off
|
|
returns the display into standard vga mode.
|
|
The value
|
|
.Ar list
|
|
lists all supported modes.
|
|
.El
|
|
.Pp
|
|
In an emergency, the bootstrap methods described in the
|
|
.Nx
|
|
installation notes for the i386 architecture
|
|
can be used to boot from floppy or other media,
|
|
or over the network.
|
|
.Sh FILES
|
|
.Bl -tag -width /usr/mdec/bootxx_fstype -compact
|
|
.It Pa /boot
|
|
boot program code loaded by the primary bootstrap
|
|
.It Pa /boot.cfg
|
|
optional configuration file
|
|
.It Pa /netbsd
|
|
system code
|
|
.It Pa /netbsd.gz
|
|
gzip-compressed system code
|
|
.It Pa /usr/mdec/boot
|
|
master copy of the boot program (copy to /boot)
|
|
.It Pa /usr/mdec/bootxx_fstype
|
|
primary bootstrap for filesystem type fstype, copied to the start of
|
|
the
|
|
.Nx
|
|
partition by
|
|
.Xr installboot 8 .
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr ddb 4 ,
|
|
.Xr pciback 4 ,
|
|
.Xr userconf 4 ,
|
|
.Xr boot.cfg 5 ,
|
|
.Xr boot_console 8 ,
|
|
.Xr dosboot 8 ,
|
|
.Xr halt 8 ,
|
|
.Xr installboot 8 ,
|
|
.Xr mbr 8 ,
|
|
.Xr multiboot 8 ,
|
|
.Xr pxeboot 8 ,
|
|
.Xr reboot 8 ,
|
|
.Xr shutdown 8 ,
|
|
.Xr w95boot 8 ,
|
|
.Xr boothowto 9
|
|
.Sh BUGS
|
|
The kernel file name must be specified before, not after, the boot options.
|
|
Any
|
|
.Ar filename
|
|
specified after the boot options, e.g.:
|
|
.Pp
|
|
.Bd -unfilled -offset indent -compact
|
|
.Cm boot -d netbsd.test
|
|
.Ed
|
|
.Pp
|
|
is ignored, and the default kernel is booted.
|
|
.Pp
|
|
Hard disks are always accessed by
|
|
.Tn BIOS
|
|
functions.
|
|
Unit numbers are
|
|
.Tn BIOS
|
|
device numbers which might differ from numbering in the
|
|
.Nx
|
|
kernel or physical parameters
|
|
.Po
|
|
e.g.,
|
|
.Tn SCSI
|
|
slave numbers
|
|
.Pc .
|
|
There isn't any distinction between
|
|
.Dq sd
|
|
and
|
|
.Dq wd
|
|
devices at the bootloader level.
|
|
This is less a bug of the bootloader code than
|
|
a shortcoming of the PC architecture.
|
|
The default disk device's name printed in the starting message
|
|
is derived from the
|
|
.Dq type
|
|
field of the
|
|
.Nx
|
|
disklabel (if it is a hard disk).
|