AUTOBOOT(ADM) UNIX System V
Name
autoboot - automatically boots the system
Description
The system can be set up to go through the boot stages
automatically (as defined in /etc/default/boot) when the
computer is turned on (booted), provided no key is pressed
at the boot(HW) prompt.
If boot times out and AUTOBOOT=YES, then the word ``auto''
is passed in the boot string and init(M) is passed a -a
flag.
In addition, the TIMEOUT entry can be set to specify the
number of seconds to wait before timing out.
The autoboot procedure checks the file /etc/default/boot for
the following instructions on autobooting:
AUTOBOOT=YES or NO Whether or not boot(HW) times out
and loads the kernel. boot looks
for this variable in the
/etc/default/boot file on its
default device.
MULTIUSER=YES or NO Whether or not init(M) invokes
sulogin or proceeds to multiuser
mode.
PANICBOOT=YES or NO Whether or not the system reboots
after a panic(). This variable
is read from /etc/default/boot by
init.
RONLYROOT=YES or NO Whether or not the root
filesystem is mounted readonly.
This must be used only during
installation, and not for a
normal boot. It will effectively
prevent writing to the
filesystem.
DEFBOOTSTR=bootstring Set default bootstring to
bootstring. This is the string
used by boot when the user
presses <RETURN> only to the
``Boot:'' prompt, or when boot
times out.
SYSTTY=x If x is 1, the system console
device is set to the serial
adapter at COM. If x is 0, the
system console is set to the main
display adapter.
SLEEPTIME=n Sets the time (in seconds)
between calls to sync.
TIMEOUT=n where n is the number of seconds
to timeout at the ``Boot:''
prompt before booting the kernel
(if AUTOBOOT=YES). If TIMEOUT is
unspecified, defaults to one
minute.
If either the /etc/default/boot file or the variable needed
cannot be found, the variable is assumed to be NO. However,
if the filesystem cannot be found, PANICBOOT is set to YES.
If the UNIX mail system, mail(C), is installed on the
system, the output of the boot sequence is mailed to root.
Otherwise, the system administrator should check the file
/etc/bootlog for the boot sequence output. The output of
fsck(ADM) is temporarily saved in the file /dev/recover
before it is moved to /etc/bootlog and finally may be sent
to the system administrator via mail.
Other boot options which take affect during autoboot are
documented on the boot(HW) manual page.
Files
/etc/bootlog boot output log for autobooting
systems
/etc/default/boot boot information file
/etc/rc2 instructions for entering multiuser
mode, includes mounting and
checking additional filesystems
/etc/sulogin executed at startup, prompts the
user to press Ctrl-d for multiuser
mode or to enter the root password
for maintenance mode
/dev/recover allows saving of fsck output
/dev/scratch temporary fsck file for large
filesystems
See Also
boot(HW), fsck(ADM), init(M)
Notes
The utilities invoked during the boot procedure are passed
the -a flag and time out only when the system autoboots.
For example, asktime(ADM) times out after 30 seconds when
the system autoboots, but waits for a response from the user
any other time it is invoked.
The previous boot modes of AUTO=CLEAN, DIRTY, NEVER have
been retained for backwards compatibility, but are ignored
if any of the newer modes are present.
Value Added
autoboot is an extension to AT&T System V developed by the
Santa Cruz Operation.
(printed 8/23/89) AUTOBOOT(ADM)