NAME
boot —
system bootstrapping
procedures
DESCRIPTION
The
NetBSD kernel is started by placing it near the
beginning of physical memory and transferring to the entry point. Since the
system is not reenterable, it is necessary to read it in from disk or the
network each time it is to be bootstrapped.
Power fail and crash
recovery
FPGA devices lose their content upon loss of power and must be re-programmed.
This is usually accomplished via a JTAG cable programmer, or using a FLASH
device. Once the eMIPS processor has been programmed into the FPGA, the system
will normally boot itself. An automatic consistency check of the file systems
will be performed, and unless this fails, the system will resume multi-user
operations.
Xilinx XUP, ML401 and ML402
On these systems the kernel is normally read in from disk. The path used for
automatic booting is
/netbsd, but it can be overridden in
the optional file
/boot.config stored in the root of the
disk filesystem. The user can also type a different filename and a combination
of boot options.
BeSquare BEE3
On this system there is no local disk and booting over the network is the only
option. Network boot can also be explicitly selected by hitting
f at the boot loader prompt.
KERNEL ARGUMENTS
At the boot loader prompt, the user may boot
NetBSD with
a number of options that are passed to the kernel unmodified. Parsing of these
options is defined in the file
/sys/boot_flag.h Some
additional flags are as follows.
-
-
e
- Empty -- this argument requests
NetBSD to ignore all symbolic information and
empty its initial symbol table.
-
-
n
- Name -- Prompt for the root file system device, the system
crash dump device, and the path to
init(8).
-
-
N
- NoName -- Do not prompt for the root file system device,
the system crash dump device, and the path to
init(8). If the
configured-in devices are present, use them.
-
-
s
- Single -- Boot only to single-user mode.
SEE ALSO
ddb(4),
halt(8),
init(8),
installboot(8),
rc(8),
reboot(8),
savecore(8),
shutdown(8)
HISTORY
The
boot command is currently under development.