NAME

reboot − UNIX bootstrapping procedures

SYNOPSIS

/etc/reboot [ options ]

DESCRIPTION

UNIX is started by placing it in memory at location zero and transferring to zero.  Since the system is not re-enterable, it must be read in from disk or tape each time it is to be bootstrapped. 

Rebooting a Running System

UNIX provides two commands for rebooting the system.   /etc/shutdown(8) reboots the system when UNIX is running with several users.  /etc/reboot reboots the system when UNIX is running without any users.  For information on /etc/shutdown(8), see the shutdown(8) man page.  This man page describes /etc/reboot. 

/etc/reboot synchronizes the disks, then initiates a multi-user reboot.  Once the system is booted, reboot performs an automatic disk check.  If the disk check completes successfully, reboot brings up the system in multi-user mode. 

Power Fail and Crash Recovery

Normally the system reboots itself when its power is turned on and after system crashes.  In both cases, the system automatically performs a consistency check of the filesystems.  Unless this check fails, the system resumes multi-user operations. 

On the IS68K, the code in the boot proms finds the specified 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.  The boot proms will boot automatically after a minute or two if nothing is typed on the system console. 

If a user has an hp disk and wishes to boot off a filesystem which starts at cylinder 0 of unit 0, she or he can type hp(0,0)vmunix to the boot prompt; hk(0,0)vmunix would specify an RK07 disk drive; el(0,0)vmunix would specify a disk drive connected to an Integrated Solutions extended rl disk controller. 

A device specification has the following form:

device(unit, minor)

in which device is the type of the device to be searched, unit is 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:

hphp disk drive
hkRK07 disk drive
rastorage module on a UDA50
elextended RL02
sddisk drive connected to VME-SCSI disk controller
smddisk drive connected to VME-SMD disk controller
tmTM11 emulation tape drives on QBUS
tsTS11 on QBUS
nwVME-NW Ethernet board (remote network boots)
exExcelan Ethernet board (remote network boots)

For tapes, the minor device number gives a file offset. 

OPTIONS

−n Does not synchronize disks.  This option can be used if a disk or the processor is fouled up. 

−q Reboots quickly and ungracefully, without first shutting down running processes. 

FILES

/vmunixsystem code

SEE ALSO

fsck(8), init(8), rc(8), shutdown(8), halt(8), newfs(8)

4th Berkeley Distribution  —  April 11, 1988