.\" Copyright (c) 1990, 1991 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the Systems Programming Group of the University of Utah Computer
.\" Science Department.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
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.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
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.\"
.\"	@(#)reboot_hp300.8	5.4 (Berkeley) 7/23/91
.\"
.Dd July 23, 1991
.Dt REBOOT 8
.Os
.Sh NAME
.Nm reboot
.Nd
.Tn UNIX
bootstrapping procedures
.Sh SYNOPSIS
.Nm reboot
.Op Fl d
.Op Fl n
.Op Fl q
.Op Fl s
.Sh DESCRIPTION
.Tn UNIX
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.
.Pp
.Sy Rebooting a running system .
When a
.Tn UNIX
is running and a reboot is desired,
.Xr shutdown 8
is normally used.
If there are no users then
.Nm reboot
can be used.
Reboot causes the disks to be synced and allows the system
to perform other shutdown activities such as resynchronizing
hardware time-of-day clocks.
A multi-user reboot (as described below) is then initiated.
This causes a system to be
booted and an automatic disk check to be performed.  If all this succeeds
without incident, the system is then brought up for many users.
.Pp
Options to reboot are:
.Bl -tag -width Ds
.\" .It Fl d
.\" option forces a memory dump to the swap area (see
.\" .Xr crash 8 )
.\" before rebooting.
.\" This can be used if the system is in a funny state that you would
.\" like to ``snapshot'' and analyze later.
.It Fl n
option avoids the sync.  It can be used if a disk or the processor
is on fire. 
.It Fl q
reboots quickly and ungracefully, without shutting down running
processes first.
.\" .It Fl s
.\" option reboots to single user mode.
.El
.Pp
.Nm Reboot
normally logs the reboot using
.Xr syslog 8
and places a shutdown record in the login accounting file (see
.Xr utmp 5 .
These actions are inhibited if the
.Fl n
or
.Fl q
options are present.
.Pp
.Sy Power fail and crash recovery.
Normally, the system will reboot 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.
.Pp
.Sy Cold starts.
On an HP300, the boot procedure uses the boot rom to load a boot program
from an
.Tn LIF
format directory at the beginning of an attached disk.
The
.Pa /usr/mdec
directory contains a disk boot program
.Pa bootrd
which should be placed in a new pack automatically by
.Xr newfs 8
when the ``a'' partition file system on the pack is created.
.Pp
This
.Em boot
program
finds the corresponding file on the given device 
.Pf ( Ar vmunix
by default),
loads that file into memory,
and starts the program at the entry address specified in the program header.
.Pp
The boot program can be interrupted by typing `^C' (ctrl-C).
This will force the boot program to interactively prompt for a system to boot.
If not interrupted, it will boot from the device from which the boot
program itself was loaded.
.Pp
The file specifications used for an interactive boot are of the form:
.Pp
.Dl device(unit,minor)
.Pp
where
.Ar device
is the type of the device to be searched,
.Ar unit
is 8 * the hpib number plus the unit number of the disk or tape,
and
.Ar minor
is the disk partition or tape file number.
Normal line editing characters can be used when typing the file specification.
Currently, ``rd'' is the only valid
.Ar device
specifier.
.Pp
For example,
to boot from the `a' file system of unit 0 on HP-IB 2,
type
.Ql rd(16,0)vmunix
to the boot prompt.
For tapes, the minor device number gives a file offset.
.Pp
In an emergency, the bootstrap methods described in the paper
.%T Installing 4.3bsd on the HP300
can be used to boot from a distribution tape.
.Sh FILES
.Bl -tag -width /usr/mdec/installboot -compact
.It Pa /vmunix
system code
.It Pa /usr/mdec/bootrd
.Tn LIF
format boot block
.It Pa /usr/mdec/installboot
program to install boot blocks
.El
.Sh SEE ALSO
.Xr crash 8m ,
.Xr fsck 8 ,
.Xr halt 8 ,
.Xr init 8 ,
.Xr newfs 8 ,
.Xr rc 8 ,
.Xr shutdown 8 ,
.Xr syslogd 8
.Sh HISTORY
The
.Nm
command is
.Ud .