.\"	$OpenBSD: boot_alpha.8,v 1.17 2023/03/13 20:32:28 miod Exp $
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.\" Copyright (c) 2002, Miodrag Vallat.
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.Dd $Mdocdate: March 13 2023 $
.Dt BOOT_ALPHA 8 alpha
.Os
.Sh NAME
.Nm boot_alpha
.Nd Alpha system bootstrapping procedures
.Sh DESCRIPTION
.Ss Cold starts
When powered on, the SRM firmware will proceed to its initialization, and
will boot an operating system if the
.Em auto_action
variable is set to
.Dq boot
or
.Dq restart ,
or will wait for interactive commands if set to
.Dq halt .
.Ss Warm starts
After a panic, or if the system is rebooted via
.Xr reboot 8
or
.Xr shutdown 8 ,
the SRM console will only restart the system if the
.Em auto_action
variable is set to
.Dq boot .
.Ss Boot process options
The SRM console will attempt to boot from the device listed in the
.Em bootdef_dev
variable.
A list of the recognized SRM devices can be obtained with the command
.Ic show dev
at the SRM prompt.
.Pp
The
.Ox
alpha boot loader program is extensively described in a separate document,
.Xr boot 8 .
.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 /usr/mdec/netboot -compact
.It Pa /bsd
default system kernel
.It Pa /bsd.rd
standalone installation kernel, suitable for disaster recovery
.It Pa /usr/mdec/bootxx
primary bootstrap for
.Dq ffs
file system
.It Pa /usr/mdec/boot
secondary bootstrap (usually also installed as
.Pa /boot )
.It Pa /usr/mdec/netboot
network bootstrap
.El
.Sh SEE ALSO
.Xr ddb 4 ,
.Xr boot 8 ,
.Xr boot_config 8 ,
.Xr halt 8 ,
.Xr init 8 ,
.Xr installboot 8 ,
.Xr reboot 8 ,
.Xr savecore 8 ,
.Xr setnetbootinfo 8 ,
.Xr shutdown 8
.Rs
.%T "Alpha Architecture Reference Manual Third Edition"
.%Q "Alpha Architecture Committee"
.%I "Digital Press"
.%D 1998
.Re
.Sh BUGS
The device names used by
.Ox Ns / Ns alpha
and the
.Tn SRM Console
often have no relation to each other.