Starting and stopping the system

Console keyboard locks up

When the system does not respond to input from the console keyboard, the situation is known as ``keyboard lockup.'' Console keyboard lockup only affects keyboards that are attached to the computer's console, not standard terminals that are attached to serial lines.

You may be experiencing keyboard lockup if all these statements are true:

The system console keyboard cannot be used to enter data or perform any tasks.
You cannot switch multiscreens, and the <CapsLock> key does not turn the CapsLock light on or off.
Other terminals on the system continue to work.
Printers or other devices continue to work, and the system is still running.

Before trying to fix a locked keyboard, make sure that:

you did not accidentally press <Ctrl>S (which stops the screen from scrolling). To check this, press <Ctrl>Q and then see if you can enter characters from the keyboard.
if your computer has a Keyboard Lock key, it is not in the locked position.
the keyboard is plugged into the correct socket.
the system itself is still running.

Check a terminal to see if it is still working and that you can perform system tasks, such as logging in and checking the date. If you do not have a terminal, watch the hard disk access light (if your computer has one).

NOTE: If you are in single-user mode, you cannot use other terminals and the hard disk access light may not flash.

If it flashes periodically (at least once every 30 seconds), the system is still running and is using the hard disk.

WARNING: Unplugging the keyboard and reconnecting it while the system is powered up can damage some computers.

If the console keyboard is still locked after checking these suggestions, try unplugging the console keyboard and plugging it in again.

If this fixes the problem, your situation is definitely keyboard lockup. If this last step does not fix the problem, you may still have keyboard lockup.

Preventing console keyboard lockup

You can prevent keyboard lockup by applying a special ``patch'' that changes the operating system kernel.

NOTE: This patch disables the keyboard lights, so you should use it only if you have tried the other approaches.

To prevent console keyboard lockup:

Get the system console working, if it is not. If necessary, reboot the system and bring it up in single-user mode by entering the root password at the Boot: prompt.
If you did not reboot, log in as root on the system console and shut the system down to single-user mode with the shutdown(ADM) command:

/etc/shutdown su
Once the system is in single-user mode, enter these commands:

umount /stand
mount /stand
This unmounts the /stand filesystem (which is normally mounted read-only) and remounts it so that you can make modifications.
Back up the kernel with these commands:

cd /stand
cp unix unix.00
Patch the kernel with these commands:

/etc/_fst -w /unix
ledspresent/w 0
$q
Shut down the system using /etc/shutdown.
When you see the Normal System Shutdown message, press any key to reboot the system. You have now fixed the keyboard lockup problem. Confirm that the keyboard is functioning normally. If you have no problems, you should now apply this fix permanently:

cd /etc/conf/pack.d/cn
copy -om Driver.o Driver.o.save
/etc/_fst -w Driver.o
ledspresent/w 0
$q

Wrong console keyboard type

If your console keyboard is an XT or other non-AT keyboard and the operating system is configured for use with an AT keyboard, the system does not recognize input from the keyboard. For information on testing and switching keyboard modes, see ``Setting the console keyboard type''.