+.\" Copyright (c) 1980 Regents of the University of California.
+.\" All rights reserved. The Berkeley software License Agreement
+.\" specifies the terms and conditions for redistribution.
+.\"
+.\" @(#)boot_vax.8 4.1 (Berkeley) %G%
+.\"
+.TH REBOOT 8 5/10/81
+.UC 4
+.SH NAME
+reboot \- UNIX bootstrapping procedures
+.SH SYNOPSIS
+.B /etc/reboot
+[
+.B \-n
+] [
+.B \-q
+]
+.SH DESCRIPTION
+.PP
+UNIX is started by placing it in memory
+at location zero and transferring to zero.
+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
+.B Rebooting a running system.
+When a UNIX is running and a reboot is desired,
+.IR shutdown (8)
+is normally used.
+If there are no users then
+.B /etc/reboot
+can be used.
+Reboot causes the disks to be synced, and then a multi-user
+reboot (as described below) is 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:
+.TP
+.B \-n
+option avoids the sync. It can be used if a disk or the processor
+is on fire. (It is no longer necessary to reboot after rebuilding
+the root file system.)
+.TP
+.B \-q
+reboots quickly and ungracefully, without shutting down running
+processes first.
+.PP
+.B "Power fail and crash recovery."
+Normally, the system will reboot itself at power-up or after crashes.
+Provided the auto-restart is enabled on the machine front panel,
+an automatic consistency check of the file systems will be performed
+then and unless this fails the system will resume multi-user operations.
+.PP
+.B Cold starts.
+These are processor type dependent.
+On an 11/780, there are two floppy files for each disk controller,
+both of which cause boots from unit 0 of the root file system
+of a controller located on mba0 or uba0.
+One gives a single user shell, while the other invokes the multi-user
+automatic reboot. Thus these files are HPS and HPM for the single
+and multi-user boot from MASSBUS RP06/RM03/RM05 disks,
+UPS and UPM for UNIBUS storage module controller and disks
+such as the EMULEX SC-21
+and AMPEX 9300 pair, or HKS and HKM for RK07 disks.
+.PP
+Giving the command
+.IP
+>>>BOOT HPM
+.LP
+Would boot the system from (e.g.) an RP06 and run the automatic consistency
+check as described in
+.IR fsck (8).
+(Note that it may
+be necessary to type control-P
+to gain the attention of the LSI-11 before getting the >>> prompt.)
+The command
+.IP
+>>>BOOT ANY
+.LP
+invokes a version of the boot program in a way which allows you to
+specify any system as the system to be booted.
+It reads from the console a device specification (see below) followed
+immediately by a pathname.
+.PP
+On an 11/750, the reset button will boot from the device
+selected by the front panel boot device switch. In systems
+with RK07's, position B normally selects the RK07 for boot.
+This will boot multi-user. To boot from RK07 with boot flags you
+may specify
+.IP
+>>>B/\fIn\fR DMA0
+.LP
+where, giving a \fIn\fR of 1 causes the boot program
+to ask for the name of the system to be bootstrapped,
+giving a \fIn\fR of 2 causes the boot program to come up single
+user, and a \fIn\fR of 3 causes both of these actions to occur.
+.PP
+The 11/750 boot procedure uses the boot roms to load block 0 off of
+the specified device. The /usr/mdec directory contains a number
+of bootstrap programs for the various disks which should be placed
+in a new pack via
+.IP
+cp /usr/mdec/\fIxx\fRboot /dev/\fIxx\fR?a
+.PP
+whenever a new bootable pack is to be created.
+.PP
+On both processors, the
+.I boot
+program
+finds the corresponding file on the given device, loads that file
+into memory location zero, and starts the program at the entry address
+specified in the program header (after clearing off the high bit
+of the specified entry address.)
+Normal line editing characters can be used in specifying the pathname.
+.PP
+If you have an rp06, rm05 or rm03 disk and wish to boot off of a file
+system which starts at cylinder 0 of unit 0, you can type \*(lqhp(0,0)vmunix\*(rq
+to the boot prompt; \*(lqup(0,0)vmunix\*(rq would specify
+a UNIBUS ampex 9300 drive, ``rk(0,0)vmunix'' would specify
+a RK-07 disk drive.
+.PP
+A device specification has the following form:
+.IP
+device(unit, minor)
+.PP
+where
+.I device
+is the type of the device to be searched,
+.I unit
+is 8* the mba or uba number plus
+the unit number of the device,
+and
+.I minor
+is the minor device index.
+The following list of supported devices may vary from installation to
+installation:
+.ta 5 10
+.nf
+ hp RP06, RM03, RM05, RP07 or RM80 on MASSBUS
+ up storage module drive on UNIBUS
+ ht TE16,TU45,TU77 on MASSBUS
+ hk RK07 on UNIBUS
+ tm TM11 emulation tape drives on UNIBUS
+ ts TS11 on UNIBUS
+.fi
+.PP
+For tapes, the minor device number gives a file offset.
+.PP
+In an emergency, the bootstrap methods described in the paper
+``Setting up the Fourth Berkeley Software Tape'' can be used
+to boot from a distribution tape.
+.SH FILES
+.ta \w'/usr/mdec/mboot 'u
+/vmunix system code
+.br
+/boot system bootstrap
+.SH "SEE ALSO"
+crash(8), fsck(8), init(8), rc(8), shutdown(8), halt(8)
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