NetBSD/share/man/man8/man8.i386/boot.8

.\"	$NetBSD: boot.8,v 1.5 1997/07/10 07:37:25 mikel Exp $
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.\"     @(#)boot_i386.8	8.2 (Berkeley) 4/19/94
.\"
.Dd March 13, 1997
.Dt BOOT 8 i386
.Os
.Sh NAME
.Nm boot
.Nd
system bootstrapping procedures
.Sh DESCRIPTION
.Sy Power fail and crash recovery.
Normally, the system will reboot itself at power-up or after crashes.
An automatic consistency check of the file systems will be performed,
and unless this fails, the system will resume multi-user operations.
.Pp
.Sy Cold starts.
The 386
.Tn "PC AT"
clones attempt to boot the floppy disk drive A (otherwise known as drive
0) first, and failing that, attempt to boot the hard disk C (otherwise
known as hard disk controller 1, drive 0).
The NetBSD bootblocks are loaded and started either by the BIOS, or by
a boot selector program (such as OS-BS, BOOTEASY, or the OS/2 Boot Menu)
.Pp
Once running, a prompt similar to the following will appear.
.Bd -unfilled -offset indent
>> NetBSD BOOT: 637/15360 k [1.28]
use hd(1,a)/netbsd to boot sd0 when wd0 is also installed
Boot: [[wd(0,a)]/netbsd][-adrs]] :-
.Ed
.Pp
After a short delay the system image listed will be loaded. (In the
above example, it will be
.Dq Li wd(0,a)/netbsd
which is the file
.Nm netbsd
on partition 
.Dq a
of the
.Nx
MBR partition of the first non-SCSI hard disk.)
.Pp
The default disk will be set to the disk that the boot loader was
loaded from.
To boot from an alternate disk, the full name of the device should
be given at the prompt. Alternate system images can be loaded by
just specifying the name of the image.
.Pp
The following list of supported devices may vary from installation to
installation:
.Bd -unfilled -offset indent
sd	SCSI disks on a controller recognized by the BIOS
wd	ST506, IDE, ESDI, RLL disks on a WD100[2367] or
	lookalike controller
hd	A hard disk as numbered by the BIOS. Must be used
	to boot from the second disk (D:) when it is SCSI
	and the first disk (C:) is non SCSI.
fd	5 1/4" or 3 1/2" High density floppies
.Ed
.Pp
The
.Op Fl s
flag to the boot loader will bring the system up in single-user mode.
The
.Op Fl a
flag instructs the system to prompt for the location of the root filesystem
and the primary swap partition.
The
.Op Fl r
flag instructs the system to use the compiled in value for the root
device, not the device the system image was loaded from.
The
.Op Fl d
flag to the boot loader will bring the system up in debug mode.
Here it waits for a kernel debugger connect; see
.Xr ddb 4 .
Other flags are currently ignored.
.Pp
In an emergency, the bootstrap methods described in the
.Nx
installation notes for the i386 architecture
can be used to boot from floppy.
.Sh FILES
.Bl -tag -width /usr/mdec/xxboot -compact
.It Pa /netbsd
system code
.It Pa /usr/mdec/xxboot
sector-0 boot block, xx is disk type
.It Pa /usr/mdec/bootxx
second-stage boot, xx is disk type
.El
.Sh SEE ALSO
.Xr ddb 4 ,
.Xr halt 8 ,
.Xr reboot 8 ,
.Xr shutdown 8