.\"	$OpenBSD: boot_luna88k.8,v 1.8 2023/01/12 19:37:53 miod Exp $
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.\" Copyright (c) 2004, Miodrag Vallat.
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.Dd $Mdocdate: January 12 2023 $
.Dt BOOT_LUNA88K 8 luna88k
.Os
.Sh NAME
.Nm boot_luna88k
.Nd luna88k system bootstrapping procedures
.Sh DESCRIPTION
.Ss Boot process description
When powered on, or after a system reboot, the luna88k ROM monitor will
proceed to its initialization, and will boot the operating system
configured in nvram if autoboot is enabled.
.Ss DIP switches description
The behaviour of the ROM monitor, as well as some kernel options, are
controlled through the SW1 set of DIP switches on the front panel.
.Pp
The switch positions are not the same on LUNA-88K and LUNA-88K2 models.
On LUNA-88K, a switch is enabled when in the
.Em down
position, while on the LUNA-88K2, a switch is enabled when in the
.Em up
position.
.Pp
The following SW1 switches alter the ROM monitor behaviour:
.Bl -column "Switch" "interact with ROM monitor" "Disabled"
.It Sy Switch Ta Sy Enabled Ta Sy Disabled
.It Li 1 Ta "interact with ROM monitor" Ta "auto-boot"
.It Li 2 Ta "serial console" Ta "graphics console"
.El
.Pp
The following switches alter the kernel behaviour:
.Bl -column "Switch" "interact with ROM monitor" "Disabled"
.It Sy Switch Ta Sy Enabled Ta Sy Disabled
.It Li 1 Ta "boot in single-user mode" Ta "boot in multi-user mode"
.It Li 3 Ta "prompt for root device" Ta "do not prompt for root device"
.It Li 4 Ta "enter UKC mode" Ta "do not enter UKC mode"
.El
Note that the same behaviour can be used by passing the
.Fl s ,
.Fl a ,
and
.Fl c
options respectively in the boot loader, rather than using the switches.
.Pp
For more details about the
.Dq User Kernel Configuration
mode
.Pq UKC ,
see
.Xr boot_config 8 .
.Pp
Note that the first switch controls both the kernel and the ROM monitor
behaviour.
.Ss Abnormal system termination
In case of system crashes, the kernel will usually enter the kernel
debugger,
.Xr ddb 4 ,
unless it is not present in the kernel, or it is disabled via the
.Em ddb.panic
sysctl.
Upon leaving ddb, or if ddb was not entered, the kernel will halt the system
if it was still in device configuration phase, or attempt a dump to the
configured dump device, if possible.
The crash dump will then be recovered by
.Xr savecore 8
during the next multi-user boot cycle.
It is also possible to force other behaviours from ddb.
.Sh FILES
.Bl -tag -width /bsd.rd -compact
.It Pa /bsd
default system kernel
.It Pa /bsd.rd
standalone installation kernel, suitable for disaster recovery
.El
.Sh SEE ALSO
.Xr ddb 4 ,
.Xr boot 8 ,
.Xr boot_config 8 ,
.Xr halt 8 ,
.Xr init 8 ,
.Xr reboot 8 ,
.Xr savecore 8 ,
.Xr shutdown 8