REBOOT(8) GENIX Programmer's Manual REBOOT(8)
NAME
reboot - UNIX bootstrapping procedures
SYNOPSIS
/etc/reboot [ -n ] [ -q ]
DESCRIPTION
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.
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
/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 per-
formed. 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 pro-
cessor is on fire! (It is no longer necessary to reboot after
rebuilding the root file system.)
-q reboots quickly and ungracefully, without shutting down running
processes first.
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.
Cold starts. The monitor can boot machine with following commands
Giving the command
b 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. check as described in fsck(8). The
command
k
Would load Boot program from ROM. Then can load 'vmunix from dcu
unit 1.
On both processors, the boot program finds the corresponding file on
the given device, loads that file into memory location zero, and
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REBOOT(8) GENIX Programmer's Manual REBOOT(8)
starts the program at the entry address specified in the program
header. Normal line editing characters can be used in specifying
the pathname.
A device specification has the following form:
device(unit, minor)
where device is the type of the device to be searched, unit is 8*
the dcu unit number plus the unit number of the device, and minor is
the minor device index. The following list of supported devices may
vary from installation to installation:
IMAI 20Mega byte
IMAI 60Mega byte
3M 20Mega byte
3M 60Mega byte
For tapes, the minor device number gives a file offset.
In an emergency, the bootstrap methods described in the paper ``Set-
ting up the Fourth Berkeley Software Tape'' can be used to boot from
a distribution tape.
FILES
/vmunixsystem code
/bootsystem bootstrap
SEE ALSO
crash(8), fsck(8), init(8), rc(8), shutdown(8), halt(8)
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