NAME
boot
, boot.conf
— armish-specific
bootstrap
DESCRIPTION
The main purpose of this program is to load the system kernel.
As described in boot_armish(8), this program is loaded by the firmware and provides a convenient way to load the kernel. This program acts as an enhanced boot monitor for armish systems, providing a common interface for the kernel to start from.
Basic operations include:
- Loading kernels from hard disk.
- Loading kernels compressed by gzip(1).
- Providing an interactive command line.
The sequence of its operation is as follows: initialization,
parsing the configuration file, then an interactive command line. While at
the command line you have 5 seconds to type any commands, if needed. If time
expires, the kernel will be loaded according to the current variable
settings (see the set
command). Each time a kernel
load fails, the timeout is increased by one second. The sequence of
boot
operations is as follows:
- If the file /etc/boot.conf exists on the
filesystem in slice ‘a’ on the first disk drive (wd0), open
and parse it. This file may contain any commands
boot
accepts at the interactive prompt. Though default settings usually suffice, they can be changed here. - The header line
>> OpenBSD/armish BOOT [x.xx]
is displayed to the active console, where x.xx is the version number of the
boot
program, followed by theboot>
prompt, which means you are in interactive mode and may enter commands. If you do not,
boot
will proceed to load the kernel with the current parameters after the timeout period has expired.
By default, boot
attempts to load the
kernel executable /bsd. If it fails to find the
kernel and no alternative kernel image has been specified, the system will
be unable to boot.
COMMANDS
The following commands are accepted at the
boot
prompt:
- boot [image [
-acds
]] - Boots the kernel image specified by image with any
options given. Image specification consists of a pair
device:filename; either or
both can be omitted (`:' is not needed if both are omitted), in which case
values from
boot
variables will be used.The only bootable devices, at the moment, are IDE devices connected to the internal controller; they are detected as ‘wd’ devices. Therefore, to boot kernel /bsd from slice ‘a’ on the first hard drive, specify “boot wd0a:/bsd”.
-a
- Causes the kernel to ask for the
root
device to use. -c
- Causes the kernel to go into boot_config(8) before performing autoconf(4) procedures.
-d
- Causes the kernel to drop into ddb(4) at the earliest convenient point.
-s
- Causes the kernel to boot single-user.
- echo [args]
- Displays args on the console device.
- help
- Prints a list of available commands.
- ls [directory]
- Prints contents of the specified directory in long format including: attributes and file type, owner, group, size, filename.
- reboot
- Reboots the machine by initiating a warm boot procedure.
- set [varname [value]]
- If invoked without arguments, prints a list of variables and their values.
If only varname is specified, displays contents of
that variable. If varname and
value are both specified, sets that variable to the
given value. Variables include:
addr
- Address at which to load the kernel.
debug
- Debug flag if
boot
was compiled with DEBUG defined. device
- Boot device name (e.g.,
wd0a
,wd1a
). howto
- Options to pass to the loaded kernel.
image
- File name containing the kernel image.
timeout
- Number of seconds boot will wait for human intervention before booting the default kernel image.
- time
- Displays system time and date.
FILES
- /usr/mdec/boot
- system bootstrap
- /etc/boot.conf
- system bootstrap's startup file
- /bsd
- kernel image
- /bsd.rd
- kernel image for installation/recovery
EXAMPLES
Boot the default kernel:
boot> boot
Remove the 5 second pause at boot-time permanently, causing
boot
to load the kernel immediately without
prompting:
# echo "boot" >
/etc/boot.conf
Boot the kernel named /bsd from the second
hard disk in “User Kernel Configuration” mode (see
boot_config(8)). This mechanism allows for the explicit
enabling and disabling of devices during the current boot sequence, as well
as the modification of device parameters. Once booted, such changes can be
made permanent by using
config(8)'s -e
option.
boot> boot wd1a:/bsd
-c
SEE ALSO
gzip(1), autoconf(4), ddb(4), boot_armish(8), boot_config(8), fdisk(8), reboot(8)
RFC 1950 describes the zlib library interface.
The official home page for the version of zlib used in this operating system is at http://www.gzip.org/zlib/.
HISTORY
This program was written by Michael Shalayeff for OpenBSD 2.1 on the i386 platform, and was later ported to the armish platform for OpenBSD 4.0.