BOOT_SPARC(8) OpenBSD System Manager's Manual (SPARC) BOOT_SPARC(8)NAMEboot_sparc - sparc system bootstrapping procedures
DESCRIPTION
System starts
When powered on, after a panic, or if the system is rebooted via
reboot(8) or shutdown(8), the PROM will proceed to its initialization,
and will boot an operating system if autoboot is enabled.
Boot process description
System boot blocks are installed near the start of the boot disk using
the procedure described in installboot(8). The boot program attempts to
load the kernel from the selected boot device, which must currently be an
``sd'', ``xd'' or ``xy'' disk, or an SCSI CD-ROM (``cd'') or tape drive
(``st'').
The SPARC boot ROM comes in two flavours: an ``old-style'' ROM is used in
sun4 machines, while a ``new-style'' ROM can be found on sun4c and sun4m
models. The ``new-style'' SPARC boot ROM is a full-featured Forth system
with emacs key bindings. It can be put in ``old-style'' user-interface
compatibility mode (in which case it shows a simple ``>'' prompt), but
this is essentially useless. However, by default the ROM runs in old-
mode; to enter new-mode type ``n''. The ROM then shows a Forth-style
``ok'' prompt. It is recommended to have the ROM always start in its
native ``new-style'' mode. Utter the following incantation in new-mode
to force the ROM to always start in new-mode:
ok setenv sunmon-compat? false
Old-style PROM operation
By default, the old ROM will poll for boot devices, unless the eeprom
settings are set to specify a particular boot device. The OpenBSD
bootloader will then look for a kernel named bsd by default, unless a
different filename has been specified in the boot command.
Refer to the ``PROM User's Manual'' for more information.
OpenBoot PROM version 1 operation
Older OpenBOOT PROM, as well as hybrid (dual-mode) versions operating in
compatibility mode (with the variable version2? set to false) will look
for a bootloader and kernel filename as specified by the boot-from
variable. To change the default so that OpenBSD will be loaded, type the
following:
ok setenv boot-from sd(0,0,0)bsd
Replace ``sd(0,0,0)'' with the appropriate boot device if necessary.
Autoboot is enabled by setting the auto-boot? variable to ``true'', and
is the factory default.
OpenBoot PROM version 2 operation
Version 2 OpenBOOT PROM will look for a bootloader on the device
specified by the boot-device variable. The OpenBSD bootloader will then
look for a kernel named bsd by default, unless the boot-file variable is
set, or a different filename has been specified in the boot command. To
reset this variable to its default, empty, value, type the following:
ok set-default boot-file
Autoboot is enabled by setting the auto-boot? variable to ``true'', and
is the factory default.
Boot process options
The following options are recognized:
-a Prompt for the root filesystem and swap devices after the
devices have been configured.
-c Enter the ``User Kernel Configuration'' mode upon startup
(see boot_config(8)).
-d Enter the debugger , ddb(4), as soon as the kernel console
has been initialized.
-s Boot the system single-user. The system will be booted
multi-user unless this option is specified.
Abnormal system termination
If the system crashes, it will enter the kernel debugger, ddb(4), if it
is configured in the kernel. If the crash occurred during initialization
and the debugger is not present or is exited, the kernel will halt the
system. If the crash occurred during normal operation and the debugger
is not present or is exited, the system will attempt a dump to the
configured dump device (which will be automatically recovered with
savecore(8) during the next multi-user boot cycle), and after the dump is
complete (successful or not) the kernel will attempt a reboot.
Accessing the PROM during runtime
If the sysctl(8) variable ddb.console is enabled, at any time you can
break back to the ROM by pressing the ``L1'' (also known as the ``stop
key'') and ``a'' keys at the same time (if the console is a serial port
the same is achieved by sending a ``break''), and entering machine prom
at the prompt. If you do this accidentally you can continue whatever was
in progress by typing go on an OpenBOOT PROM, or c on an old-style PROM
to return to ddb, and then cont to return to the system.
FILES
/bsd default system kernel
/bsd.rd standalone installation kernel, suitable for disaster
recovery
/usr/mdec/bootxx primary bootstrap for ``ffs'' file system
/usr/mdec/boot secondary bootstrap (usually also installed as /boot)
SEE ALSOddb(4), boot_config(8), halt(8), init(8), installboot(8), reboot(8),
savecore(8), shutdown(8)OpenBSD 4.9 January 3, 2010 OpenBSD 4.9