reboot - UNIX bootstrapping procedures

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SYNOPSIS

DESCRIPTION

UNIX is started by placing it in memory and transferring to the entry point. Since the system is not reenterable, it is necessary to read it in from disk or ethernet 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 /usr/etc/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

Avoids the sync. It can be used if a disk or the processor is on fire.

-q

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

boot_command

Allows a new boot command to be specified. Normally the system is rebooted using the previous boot command, but using this option allows a new boot command to be specified without requiring the user to halt the system and enter the new boot command from the console.

Reboot normally logs the reboot using syslog.8 and places a shutdown record in the login accounting file /usr/adm/wtmp. These actions are inhibited if the -n or -q options are present.

Cold starts. The ROM monitor automatically starts the NeXT computer when the power is turned on or when the computer is rebooted. The boot program finds the corresponding file on the given device (odmach for an optical drive, sdmach for a SCSI drive), loads that file into memory, and starts the program at the entry address specified in the program header (after clearing off the high bit of the specified entry address).

If you want to stop the boot sequence, hold down the Command key and press the backquote key on the numeric keypad -- the ROM monitor will display a text window containing the "NeXT>" prompt. You can then use the ROM monitor's boot command (b) to start the boot sequence over, possibly specifying a different boot device.

The syntax of the b boot command is:

device[(ctrl,unit,part)][file][flags]

where device is the type of the device to be searched, ctrl is the controller number, unit is the unit number of the disk or tape, and part is the disk partition number. Possible values for flags are:

-a

Ask for the name of the root device

-b

Don't process the rc.boot file

-s

Boot in single-user mode instead of multi-user mode

-i

Ask for the name of the init program (the default is /usr/etc/init)

-p

Don't automatically reboot after a system panic

The following devices are supported:

sd

SCSI disk drive

od

optical disk drive

en

ethernet

FILES

SEE ALSO

Created by unroff & hp-tools. © somebody (See intro for details). All Rights Reserved. Last modified 11/5/97