xref: /netbsd-src/share/man/man8/boot.8 (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1.\"	$NetBSD: boot.8,v 1.12 2009/09/04 23:29:02 apb Exp $
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33.\"     @(#)boot_i386.8	8.2 (Berkeley) 4/19/94
34.\"
35.Dd September 4, 2009
36.Dt BOOT 8
37.Os
38.Sh NAME
39.Nm boot
40.Nd
41system bootstrapping procedures
42.Sh DESCRIPTION
43This document provides information on using common features in the
44.Nx
45boot loader.
46Additional information may be found in
47architecture-specific
48.Xr boot 8
49manual pages.
50.Pp
51In the native
52.Nx
53boot protocol, options are passed from the boot loader
54to the kernel via flag bits in the
55.Va boothowto
56variable (see
57.Xr boothowto 9 ) .
58.Ss Interactive mode
59In interactive mode, the boot loader will present a prompt, allowing
60input of these commands:
61.\" NOTE: much of this text is duplicated in architecture-specific
62.\" man pages (man8/man8.*/*boot*.8);
63.\" please try to keep all relevant files synchronized.
64.Bl -tag -width 04n -offset 04n
65.It Ic boot Oo Va device : Ns Oc Oo Va filename Oc Oo Fl 1234abcdmqsvxz Oc
66The default
67.Va device
68will be set to the disk that the boot loader was
69loaded from.
70To boot from an alternate disk, the full name of the device should
71be given at the prompt.
72.Va device
73is of the form
74.Xo Va xd
75.Op Va N Ns Op Va x
76.Xc
77where
78.Va xd
79is the device from which to boot,
80.Va N
81is the unit number, and
82.Va x
83is the partition letter.
84.Pp
85The following list of supported devices may vary from installation to
86installation:
87.Pp
88.Bl -hang -compact
89.It hd
90Hard disks.
91.It fd
92Floppy drives.
93.El
94.Pp
95The default
96.Va filename
97is
98.Pa netbsd ;
99if the boot loader fails to successfully
100open that image, it then tries
101.Pa netbsd.gz
102(expected to be a kernel image compressed by gzip), followed by
103.Pa netbsd.old ,
104.Pa netbsd.old.gz ,
105.Pa onetbsd ,
106and finally
107.Pa onetbsd.gz .
108Alternate system images can be loaded by just specifying the name of the image.
109.Pp
110Options are:
111.Bl -tag -width xxx
112.It Fl 1
113Sets the machine-dependent flag
114.Sy RB_MD1
115in
116.Va boothowto .
117.It Fl 2
118Sets the machine-dependent flag
119.Sy RB_MD2
120in
121.Va boothowto .
122.It Fl 3
123Sets the machine-dependent flag
124.Sy RB_MD3
125in
126.Va boothowto .
127.It Fl 4
128Sets the machine-dependent flag
129.Sy RB_MD4
130in
131.Va boothowto .
132.It Fl a
133Sets the
134.Sy RB_ASKNAME
135flag in
136.Va boothowto .
137This causes the kernel to prompt for the root file system device,
138the system crash dump device, and the path to
139.Xr init 8 .
140.It Fl b
141Sets the
142.Sy RB_HALT
143flag in
144.Va boothowto .
145This causes subsequent reboot attempts to halt instead of rebooting.
146.It Fl c
147Sets the
148.Sy RB_USERCONF
149flag in
150.Va boothowto .
151This causes the kernel to enter the
152.Xr userconf 4
153device configuration manager as soon as possible during the boot.
154.Xr userconf 4
155allows devices to be enabled or disabled, and allows device locators
156(such as hardware addresses or bus numbers)
157to be modified before the kernel attempts to attach the devices.
158.It Fl d
159Sets the
160.Sy RB_KDB
161flag in
162.Va boothowto .
163Requests the kernel to enter debug mode, in which it
164waits for a connection from a kernel debugger; see
165.Xr ddb 4 .
166.It Fl m
167Sets the
168.Sy RB_MINIROOT
169flag in
170.Va boothowto .
171Informs the kernel that a mini-root file system is present in memory.
172.It Fl q
173Sets the
174.Sy AB_QUIET
175flag in
176.Va boothowto .
177Boot the system in quiet mode.
178.It Fl s
179Sets the
180.Sy RB_SINGLE
181flag in
182.Va boothowto .
183Boot the system in single-user mode.
184.It Fl v
185Sets the
186.Sy AB_VERBOSE
187flag in
188.Va boothowto .
189Boot the system in verbose mode.
190.It Fl x
191Sets the
192.Sy AB_DEBUG
193flag in
194.Va boothowto .
195Boot the system with debug messages enabled.
196.It Fl z
197Sets the
198.Sy AB_SILENT
199flag in
200.Va boothowto .
201Boot the system in silent mode.
202.El
203.It Ic consdev Va dev
204Immediately switch the console to the specified device
205.Va dev
206and reprint the banner.
207.Va dev
208must be one of
209.\" .Bl -item -width com[0123]kbd -offset indent -compact
210.Ar pc , com0 , com1 , com2 ,
211.Ar com3 , com0kbd , com1kbd , com2kbd ,
212.Ar com3kbd ,
213or
214.Ar auto .
215See
216.Sx Console Selection Policy
217in
218.Xr boot_console 8 .
219.It Ic dev Op Va device
220Set the default drive and partition for subsequent filesystem
221operations.
222Without an argument, print the current setting.
223.Va device
224is of the form specified in
225.Cm boot .
226.It Ic help
227Print an overview about commands and arguments.
228.\" .It Ic load Va module Op Va arguments
229.\" [i386 only]
230.It Ic ls Op Pa path
231Print a directory listing of
232.Pa path ,
233containing inode number, filename, and file type.
234.Pa path
235can contain a device specification.
236.\" .It Ic multiboot Va kernel Op Va arguments
237.\" [i386 only]
238.It Ic quit
239Reboot the system.
240.El
241.Pp
242In an emergency, the bootstrap methods described in the
243.Nx
244installation notes for the specific architecture
245can be used.
246.Sh FILES
247.Bl -tag -width /usr/mdec/bootxx_fstype -compact
248.It Pa /boot
249boot program code loaded by the primary bootstrap
250.\" .It Pa /boot.cfg
251.\" optional configuration file
252.\" (used only on i386 and amd64 architectures)
253.It Pa /netbsd
254system code
255.It Pa /netbsd.gz
256gzip-compressed system code
257.It Pa /usr/mdec/boot
258master copy of the boot program (copy to /boot)
259.It Pa /usr/mdec/bootxx_fstype
260primary bootstrap for filesystem type fstype, copied to the start of
261the
262.Nx
263partition by
264.Xr installboot 8 .
265.El
266.Sh SEE ALSO
267Architecture-specific
268.Xr boot 8
269manual pages,
270.Xr ddb 4 ,
271.Xr userconf 4 ,
272.\" .Xr boot.cfg 5 ,
273.Xr halt 8 ,
274.Xr installboot 8 ,
275.Xr reboot 8 ,
276.Xr rescue 8 ,
277.Xr shutdown 8 ,
278.Xr boothowto 9
279.Sh BUGS
280The kernel file name must be specified before, not after, the boot options.
281Any
282.Ar filename
283specified after the boot options, e.g.:
284.Pp
285.Bd -unfilled -offset indent -compact
286.Cm boot -d netbsd.test
287.Ed
288.Pp
289is ignored, and the default kernel is booted.
290