System information

6 Hardware Monitor Functionality
• Validation of the automatic BIOS CMOS setup by the CHARM card.
• Inspection of the BIOS boot messages.
• Analysis of the screen content after a system crash.
The advantage of this approach is the possibility of the automatic validation and analysis of
the screen content. Figure 6.5 shows the boot screen of a computer running in a graphical
video mode. The program getscreen inspects the VGA content and returns the textual
representation of the screen content. Figure 6.6 shows the result of the character recognition.
The average processing time of the getscreen program for a video resolution of 640x480 pixels
and a color depth of 4 bits is approximately 2 seconds. Unknown character patterns can be
returned as an arbitrary but fixed character, e.g. a space or an "X".
Figure 6.5: Screenshot of the boot screen of
an HLT cluster node.
Figure 6.6: Alphanumerical output of the
screen content.
6.3.2 Previous Content of the Screen
After a system crash, the screen content can provide information about the cause of the
failure. As mentioned above, information about a current Linux kernel panic is print out
to the screen. However, the message of the kernel panic should not be the last text content
which is printed on the screen. The output buffer of the text console could contain other
pending messages. These messages can be print out after the kernel message and scroll the
previous text content out of view. In this case, there is no possibility to read the kernel
message if the system crashes. But a VGA card can still contain the message inside the
video plane. To reduce the data traffic, a VGA card provides a pointer which marks the
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