BOOT(8)            OpenBSD System Manager's Manual (LANDISK)           BOOT(8)

NAME
     boot, boot.conf - landisk-specific second-stage bootstrap

DESCRIPTION
     The main purpose of this program is to load the system kernel from the
     root file system of the machine.

     As described in boot_landisk(8), this program is loaded by the xxboot(8)
     primary bootstrap loader and provides a convenient way to load the ker-
     nel.  This program acts as an enhanced boot monitor for landisk systems,
     providing a common interface for the kernel to start from.

     Basic operations include:

     o   Loading kernels from any device supported by your system firmware.
     o   Loading kernels compressed by gzip(1).
     o   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 com-
     mand line you have 5 seconds to type any commands, if needed.  If time
     expires, the kernel will be loaded according to the current variable set-
     tings (see the set command).  Each time a kernel load fails, the timeout
     is increased by one second.  The sequence of boot operations is as fol-
     lows:

     1.   If the file /etc/boot.conf exists on the filesystem boot was loaded
          from, 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.

     2.   The header line

                >> OpenBSD/landisk BOOT [x.xx]

          is displayed to the active console, where x.xx is the version number
          of the boot program, followed by the

                boot>

          prompt, which means you are in interactive mode and may enter com-
          mands.  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 speci-
     fied, 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 giv-
              en.  Image specification consists of a pair device:filename; ei-
              ther or both can be omitted (`:' is not needed if both are omit-
              ted), in which case values from boot variables will be used.

              The only bootable device, at the moment, is the internal IDE de-
              vice (either a compactflash media or an ATA disk drive), and is
              named `cf'.  Therefore, to boot kernel /bsd from the internal
              drive, specify ``boot cf:/bsd''.

              -a   Causes the kernel to ask for the root device to use.

              -c   Causes the kernel to go into boot_config(8) before perform-
                   ing autoconf(4) procedures.

              -d   Causes the kernel to drop into ddb(4) at the earliest con-
                   venient 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 in-
              cluding: 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.
              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
     /boot             system bootstrap
     /etc/boot.conf    system bootstrap's startup file
     /bsd              kernel image
     /bsd.rd           kernel image for installation/recovery
     /usr/mdec/xxboot  first stage bootstrap

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.rd 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 cf:/bsd.rd -c

SEE ALSO
     gzip(1), autoconf(4), ddb(4), boot_config(8), boot_landisk(8), fdisk(8),
     reboot(8), xxboot(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 4.1.

OpenBSD 4.7                      May 28, 2008                                3
