REBOOT(8) REBOOT(8)
NAME
reboot - bootstrapping procedures
DESCRIPTION
Here are some recipes for booting and crashing the operating
system on VAXes.
Rebooting a running system
The preferred way to reboot is to log in on the console as
super-user, invoke kill 1 to take the system to single user,
unmount file systems with /etc/umount -a and halt and res-
tart the system as described below under `Console boots.'
Power fail and crash recovery
The system will reboot itself at power-up or after crashes
if auto-boot is enabled on the machine front panel or in the
console software. If auto-restart is enabled, the system
will first attempt to save a copy of physical memory on a
reserved piece of disk. An automatic consistency check of
the file systems is performed. Unless this fails the system
will resume multi-user operations.
Console boots
Sync the disks if necessary and possible. To recover hard-
ware control of the console, type a control-P. This will
yield a `>>>' prompt from the VAX console subsystem (sic).
The command
>>> H
will halt the CPU (except on the 11/750, where control-P
halts the CPU right away).
On MicroVAXes, control-P doesn't work; hit the BREAK key
instead.
To boot multi-user with an automatic file system check, give
the console command
>>> B
Commands to boot single-user vary. On the VAX-11/750 and on
MicroVAXes, use
>>> B/3
On the VAX-11/780 and VAX 8550 and 8700, use
>>> B MAN
REBOOT(8) REBOOT(8)
This will prompt with `*' for the name of the file to boot.
The filename should be an executable image in the root
directory of the filesystem at the beginning of the disk.
System core images
If the system crashes and auto-restart is enabled, a copy of
physical memory is written to a reserved piece of disk. To
save a core image of a hung system, type on the console
(after control-P if necessary):
>>> S 80000010
The system will write the core image, then reboot automati-
cally.
If the core image was written on `/dev/ra11', the following
incantation will print a stack traceback from the time of
the crash:
adb /unix /dev/ra11
$<crash
$c
To save disk space, the core image is sometimes overlaid on
part of the swap area, where normal system operation will
soon overwrite it. Savecore(8) will copy the core image to
an ordinary disk file.
FILES
default system binary
SEE ALSO
fsck(8), init(8), rc(8), savecore(8)
BUGS
Older boot programs with different syntax are still around
in a few places, especially on machines with Emulex UNIBUS
disk controllers, for which silly boot ROMs are common.
There are commands /etc/reboot and /etc/halt which attempt
to reboot and halt the system; their function is indetermi-
nate and likely to change.