BOOT_PMAX(8)        OpenBSD System Manager's Manual (PMAX)        BOOT_PMAX(8)

NAME
     boot - sparc-specific system bootstrapping procedures

DESCRIPTION
     The OpenBSD kernel is started by placing it at 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 tape each time it
     is to be bootstrapped.

   Power fail and crash recovery
     Normally, the system will boot itself at power-up or after crashes.  An
     automatic consistency check of the file systems will be performed, and
     unless this fails, the system will resume multi-user operations.

   Cold starts
     At power up, all DECstation ROMs consult the haltaction environment vari-
     able in EEPROM to determine whether or not to attempt an automatic boot.
     If this variable is set to ``h'', the ROM prints a prompt on the console
     and waits for user commands.  If set to ``b'', the ROM attempts to auto-
     boot.

     On the DECstation 2100 and 3100, the path used for automatic booting is
     stored in the bootpath environment variable.  The path is made up of a
     device type specifier (e.g., rz, tz, mop or tftp), followed by a triplet
     in the form (x,y,z), followed by a filename to load.

     Within the triplet, ``x'' is the controller (always 0), ``y'' is the SCSI
     ID of the drive to boot from or 0 for net boots, and ``z'' is the parti-
     tion to boot from (usually 0 for SCSI devices, always zero for network
     booting).  For network boots, () may be specified instead of (0,0,0).

     The filename is optional for bootp/tftp and mop booting, since in these
     cases the network protocol can be used to determine which file to boot.
     When booting off the tape, no filename should be specified, and when
     booting off disk, the filename of a kernel must be specified.  Generally,
     the kernel is named bsd.

     An example bootpath setting would be:

           setenv bootpath rz(0,1,0)bsd

     For automatic boots, the ROM automatically passes a -a argument to the
     bootloader, requesting that OpenBSD attempt to come up to multi-user
     mode.  At the boot ROM prompt, the user may boot OpenBSD with either the
     auto or the boot command.  If the auto command is used, the -a argument
     is passed to the kernel, requesting a multi-user boot; otherwise the -s
     argument is passed, requesting that OpenBSD boot to single user mode.

     When either the boot or the auto command is issued with no arguments, the
     kernel specified in the bootpath environment variable is booted.  An al-
     ternate kernel may be specified with the -f flag, followed by the path of
     the kernel to boot, as described above.  For example:

           boot -f rz(0,4,0)bsd.new

     On TurboChannel machines (all DECstation 5000 models), the bootpath is
     specified in the boot environment variable, along with any arguments to
     be passed to the kernel.  Note that to specify boot arguments (e.g., -a)
     when setting the boot environment variable, the filename and arguments
     must be enclosed in quotes.  For example:

           setenv boot 3/rz4/bsd -a

     The device from which to boot is specified as the TurboChannel slot num-
     ber, a TurboChannel-option-specific device name, and a path to the file
     to load, all separated by slashes.  You can get a list of the devices in-
     stalled in your TurboChannel slots (as well as any built-in devices which
     appear as TurboChannel slots) by typing the cnfg command at the boot
     prompt.  You can get more detailed information about a specific Tur-
     boChannel option by typing cnfg followed by the slot number of that op-
     tion.

     For SCSI devices, the option-specific device identifier is either ``rz#''
     for disks or ``tz#'' for tapes, where # is the SCSI ID of the device.
     For network devices, the option-specific protocol identifier is either
     mop or tftp.  Filename requirements are as for the DECstation 2100 and
     3100.

     To start OpenBSD from the boot prompt, the boot command must be used.
     With no arguments, this simply boots the default kernel with the default
     arguments as set with setenv boot. If no boot environment variable is
     set, or if an alternate kernel is to be booted, the path of that kernel
     may be specified after the boot command as described above, and any argu-
     ments may be passed similarly.  For example:

           boot 3/rz4/bsd.new -a

SEE ALSO
     crash(8), fsck(8), halt(8), init(8), newfs(8), rc(8), reboot(8),
     shutdown(8), syslogd(8)

OpenBSD 2.8                      July 23, 1991                               2
