System information

7 Automatic Cluster Management

# Power on the node

hostPowerOn

while (hostPOSTcode != 0x37); # 0x37 = (Displaying sign-on message)

# Send/push "delete key" to enter setup

keyb_cmd -u --key 0x7e335b1b -s

The POST code 0x37 represents the display of the BIOS start-up screen with the sign-on

message [79]. This is the moment, to push the "delete" button to enter the BIOS setup

utility. With the aid of the program key_cmd single keystrokes can be emulated. The

parameter –key deﬁnes the ASCII representation of the pressed key. There are no ASCII

codes for special function keys like the "delete" or the "arrow" keys [87]. In this case, the

ANSI escape codes are used to select a function key [88]. The value 0x7e335b1b is the

escape sequence of the "delete" key. Next a code fragment is shown which waits for the

entering of the BIOS Setup Utility:

while (true)

case (hostPOSTcode) in

"0x87" ) break # 0x87 = (Execute BIOS setup if requested.)

"0x85" ) analyseError # 0x85 = (Display errors to the user.)

esac

done

The inﬁnite while loop is used to wait for the start of the BIOS setup utility. The original

shell script contains a timeout to avoid an inﬁnite run of the script. The advantage of

detecting the boot stage with the POST codes is that it is independent of the motherboard

or BIOS vendor. Furthermore, the CHARM can analyze the screen content to detect the

state of the booting or to validate the setup of the BIOS setting. Unfortunately, most of

the BIOS run in a graphical video mode and the screen content contains pixel data instead

of ASCII characters. But with the aid of the Display Screen Inspector the pixel data can be

converted into ASCII characters (section 6.3 explains this approach). However, analyzing

the screen content to detect the boot state highly depends on the host system, whereas the

basic POST code set depends only on the BIOS vendor. Basically, two vendors provide the

most of the BIOS for computer systems: American Megatrends and Phoenix Technologies.

The CMOS setup script can easily be ported to other computer systems. After entering the

BIOS Setup Utility, the key sequence of the appropriated BIOS setup is sent to the host

computer:

# Send key sequence to load the default BIOS setting

for key in $ANSI_LEFT $ANSI_DOWN $ANSI_DOWN $ASCII_ENTER ...

keyb_cmd -u --key $key -s

done

# Send key sequence to setup and save the desired BIOS setting