REBOOT(8)REBOOT(8)NAME
reboot - UNIX bootstrapping procedures
SYNOPSIS
reboot [ -n ] [ -q ]
DESCRIPTION
UNIX is started by placing it in memory at location zero and transfer‐
ring 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 boot‐
strapped.
Rebooting a running system. When a UNIX is running and a reboot is
desired, shutdown(8) is normally used. If there are no users then
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.
Options to reboot are:
-n option avoids the sync. It can be used if a disk or the proces‐
sor is on fire.
-q reboots quickly and ungracefully, without shutting down running
processes first.
Reboot normally logs the reboot using syslog(8) and places a shutdown
record in the login accounting file /var/log/wtmp. These actions are
inhibited if the -n or -q options are present.
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, and unless this fails, the system will
resume multi-user operations.
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, RAS and RAM to boot from MSCP con‐
trollers and disks such as the RA81, or HKS and HKM for RK07 disks.
There is also a script for booting from the default device, which is
normally a copy of one of the standard multi-user boot scripts, but
which may be modified to perform other actions or to boot from a dif‐
ferent unit. The situation on the 8600 is similar, with scripts loaded
from the console RL02.
Giving the command
>>>BOOT HPM
would boot the system from (e.g.) an RP06 and run the automatic consis‐
tency check as described in fsck(8). (Note that it may be necessary to
type control-P and halt the processor to gain the attention of the
LSI-11 before getting the >>> prompt.) The command
>>>BOOT ANY
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 con‐
sole a device specification (see below) followed immediately by a path‐
name.
The scripts may be modified for local configuration if necessary. The
flags are placed in register 11 (as defined in <sys/reboot.h>). The
boot device is specified in register 10. The encoding of this register
is also defined in <sys/reboot.h>. The current encoding has a histori‐
cal basis, and is shown in the following table:
bits usage
0-7 boot device type (the device major number)
8-15 disk partition
16-19drive unit
20-23controller number
24-27adaptor number (UNIBUS or MASSBUS as appropriate)
The adaptor number corresponds to the normal configuration on the
11/750, and to the order in which adaptors are found on the 11/780 and
8600 (generally the same as the numbers used by UNIX).
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
>>>B/n DMA0
where, giving a n of 1 causes the boot program to ask for the name of
the system to be bootstrapped, giving a n of 2 causes the boot program
to come up single user, and a n of 3 causes both of these actions to
occur. The ``DM'' specifies RK07, the ``A'' represents the adaptor
number (UNIBUS or MASSBUS), and the ``0'' is the drive unit number.
Other disk types which may be used are DB (MASSBUS), DD (TU58), and DU
(UDA-50/RA disk). A non-zero disk partition can be used by adding
(partition times 1000 hex) to n.
The boot procedure on the MicroVAX II is similar. A switch on the back
panel sets the power-up action to autoboot or to halt. When halted,
the processor may be booted using the same syntax as on the 11/750.
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 boot‐
strap programs for the various disks which should be placed in a new
pack by disklabel(8). Similarly, the MicroVAX II boot procedure loads
a boot parameter block from block 0 of the disk. The rdboot ``boot‐
strap'' contains the correct parameters for an MSCP disk such as the
RD53.
On any processor, the boot program finds the corresponding file on the
given device (vmunix by default), loads that file into memory location
zero, and starts the program at the entry address specified in the pro‐
gram header (after clearing off the high bit of the specified entry
address).
The file specifications used with “BOOT ANY” or “B/3” are of the form:
device(adaptor,controller,unit,minor)
where device is the type of the device to be searched, adaptor is the
UNIBUS or MASSBUS number of the adaptor to which the device is
attached, controller is the unit number of the controller or MASSBUS
tape formatter on that adaptor, unit is the unit number of the disk or
transport slave unit of the tape, and minor is the disk partition or
tape file number. Leading adaptor or controller numbers default to 0.
Normal line editing characters can be used when typing the file speci‐
fication. The following list of supported devices may vary from
installation to installation:
hp MASSBUS disk drive
up UNIBUS storage module drive
ht TE16,TU45,TU77 on MASSBUS
kra storage module on a KDB50
mt TU78 on MASSBUS
hk RK07 on UNIBUS
ra storage module on a MSCP-compatible UNIBUS controller
rb storage module on a 730 IDC
rl RL02 on UNIBUS
tm TM11 emulation tape drives on UNIBUS
tms TMSCP-compatible tape
ts TS11 on UNIBUS
ut UNIBUS TU45 emulator
For example, to boot from a file system which starts at cylinder 0 of
unit 0 of a MASSBUS disk, type “hp(0,0)vmunix” to the boot prompt;
“hp(2,0,1,0)vmunix” would specify drive 1 on MASSBUS adaptor 2;
“up(0,0)vmunix” would specify a UNIBUS drive, “hk(0,0)vmunix” would
specify an RK07 disk drive, “ra(1,0,0,0)vmunix” would specify a UDA50
disk drive on a second UNIBUS, and “rb(0,0)vmunix” would specify a disk
on a 730 IDC. For tapes, the minor device number gives a file offset;
“mt(1,2,3,4)” would specify the fifth file on slave 3 of the formatter
at “drive” 2 on mba 1.
On an 11/750 with patchable control store, microcode patches will be
installed by boot if the file psc750.bin exists in the root of the
filesystem from which the system is booted.
In an emergency, the bootstrap methods described in the paper
``Installing and Operating 4.3bsd'' can be used to boot from a distri‐
bution tape.
FILES
/vmunix system code
/boot system bootstrap
/usr/mdec/xxboot sector-0 boot block for 750, xx is disk type
/usr/mdec/bootxx second-stage boot for 750, xx is disk type
/pcs750.bin microcode patch file on 750
SEE ALSOarff(8V), crash(8V), disklabel(8), fsck(8), halt(8), init(8), rc(8),
shutdown(8), syslogd(8)4th Berkeley Distribution June 24, 1990 REBOOT(8)
