boot(8) - NetBSD Manual Pages

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BOOT(8)                 NetBSD System Manager's Manual                 BOOT(8)


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-pro-
     grammed.  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
     otions 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 fol-
     lows.

           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.

NetBSD 6.0.3                     July 17, 2010                    NetBSD 6.0.3