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34 .Dd April 8, 2003
35 .Dt BOOT 8 pmax
36 .Os
37 .Sh NAME
38 .Nm boot
39 .Nd system bootstrapping procedures
40 .Sh DESCRIPTION
41 The
42 .Nx
43 kernel is started by placing it near the beginning of physical
44 memory and transferring to the entry point.
45 Since the system is not reenterable,
46 it is necessary to read it in from disk or tape
47 each time it is to be bootstrapped.
48 .Ss Power fail and crash recovery
49 Normally, the system will boot itself at power-up or after crashes.
50 An automatic consistency check of the file systems will be performed,
51 and unless this fails, the system will resume multi-user operations.
52 .Ss Cold starts
53 At power up, all DECstation ROMs consult the
54 .Nm haltaction
55 environment
56 variable in EEPROM to determine whether or not to attempt to boot
57 automatically.
58 If this variable is set to
59 .Sq h ,
60 the ROM prints a prompt on the console and
61 waits for user commands.
62 If set to
63 .Sq b ,
64 the ROM attempts to autoboot.
65 .Sh DECSTATION 2100 and 3100
66 On the DECstation 2100 and 3100, the path used for automatic booting is
67 stored in the
68 .Nm bootpath
69 environment variable.
70 The path is made up of a
71 device type specifier (e.g., rz, tz, mop or tftp) followed by
72 a triplet in the form (x,y,z), followed by a filename to load.
73 .Pp
74 Within the triplet, x is the controller (always 0), y is the SCSI id of
75 the drive to
76 boot from or 0 for net boots, and z is the partition to boot from
77 (usually 0 for SCSI devices, always zero for network booting).
78 For both disk and network boots, () may be specified instead of
79 (0,0,0).
80 .Pp
81 The filename is optional for bootp/tftp and mop booting, since in
82 these cases the network protocol can be used to determine which
83 file to boot.
84 When booting off the tape, no filename should be specified.
85 When booting off of disk, the filename is optional but is usually specified.
86 If no filename is specified when booting off disk, the following
87 filenames are tried in order:
88 .Nm netbsd.pmax ,
89 .Nm netbsd ,
90 .Nm netbsd.gz ,
91 .Nm netbsd.bak ,
92 .Nm netbsd.old ,
93 .Nm onetbsd ,
94 .Nm gennetbsd .
95 Generally, the kernel is named
96 .Nm netbsd .
97 .Pp
98 An example bootpath setting would be:
99 .Dl Ic setenv bootpath rz(0,1,0)netbsd
100 .Pp
101 At the PROM prompt, the user may boot
102 .Nx
103 with either the
104 .Nm auto
105 or the
106 .Nm boot
107 command.
108 If the
109 .Nm auto
110 command is used, the
111 .Fl a
112 argument is passed to the kernel, requesting a multi-user boot; otherwise
113 the
114 .Fl s
115 argument is passed, requesting that
116 .Nx
117 boot to single user mode.
118 .Pp
119 When either the
120 .Nm boot
121 or the
122 .Nm auto
123 command is issued with no arguments, the kernel specified in the bootpath
124 environment variable is booted.
125 With the
126 .Nm boot
127 command, an alternative kernel may be specified
128 with the
129 .Fl f
130 flag, followed by the path of the kernel to boot, as described above.
131 For example:
132 .Dl Ic boot -f rz(0,4,0)netbsd.new
133 .Sh TURBOCHANNEL DECstations
134 On TurboChannel machines (all DECstation 5000 models), the boot path
135 is specified in the boot environment variable, along with any arguments
136 to be passed to the kernel.
137 Note that to specify boot arguments (e.g.,
138 .Fl a )
139 when setting the
140 .Nm boot
141 environment variable, the filename and arguments
142 must be enclosed in quotes.
143 For example:
144 .Dl Ic setenv boot Dq Ic "3/rz4/netbsd -a"
145 .Pp
146 The device from which to boot is specified as the TurboChannel slot
147 number, a TurboChannel-option-specific device name, and a path to the
148 file to load, all separated by slashes.
149 You can get a list of the
150 devices installed in your TurboChannel slots (as well as any built-in
151 devices which appear as TurboChannel slots) by typing the
152 .Nm cnfg
153 command
154 at the boot prompt.
155 You can get more detailed information about a specific
156 TurboChannel option by typing
157 .Nm cnfg
158 followed by the slot number of that
159 option.
160 .Pp
161 For SCSI devices, the option-specific device identifier is either rz# for
162 disks or tz# for tapes, where # is the SCSI id of the device.
163 For network
164 devices, the option-specific protocol identifier is either mop or tftp.
165 Filename requirements are as for the DECstation 2100 and 3100.
166 .Pp
167 To start
168 .Nx
169 from the boot prompt, the
170 .Nm boot
171 command must be used.
172 With no arguments, this simply boots the default
173 kernel with the default arguments as set with
174 .Nm setenv
175 .Nm boot .
176 If no boot environment variable is set or if an alternative kernel is to be
177 booted, the path of that kernel may be specified after the boot command as
178 described above, and any arguments may be passed similarly.
179 For example:
180 .Dl Ic boot 3/rz4/netbsd.new -a
181 .Sh KERNEL ARGUMENTS
182 The kernel supports the following arguments:
183 .Bl -tag -width xxx -offset indent
184 .It Li a
185 Autoboot -- try and boot to multi-user mode without
186 further input.
187 .It Li m
188 Use a miniroot already present in memory.
189 .It Li n
190 Prompt for the root file system device, the system crash dump
191 device, and the path to
192 .Xr init 8 .
193 .It Li N
194 Do not prompt for the root file system device, the system crash dump
195 device, and the path to
196 .Xr init 8 .
197 If the configured-in devices are present, use them.
198 .It Li s
199 Boot only to single-user mode.
200 .El
201 .Pp
202 Since DECstation PROMs also parse any arguments with a leading
203 "-", and reject unrecognized options, arguments other than "a" or "s"
204 should be specified after the kernel name with no leading "-".
205 For example:
206 .Dl Ic boot 3/rz4/netbsd \&ns
207 .Sh SEE ALSO
208 .Xr ddb 4 ,
209 .Xr halt 8 ,
210 .Xr init 8 ,
211 .Xr installboot 8 ,
212 .Xr rc 8 ,
213 .Xr reboot 8 ,
214 .Xr savecore 8 ,
215 .Xr shutdown 8
216 .Sh HISTORY
217 The
218 .Nm
219 command is
220 .Ud