On (older)
rs/6000 CPUs what the diagnostic
LED's* would
flash when the
kernel panics.
Flashing 888 on these AIX systems are a clear indication that the machine
has crashed and needs to be rebooted. Post-crash
frobbing of the reset button will cycle the diagnostic
processor display through a series of codes. These codes indicate the
nature of the failure (software, hardware and possibly which subsystem
crashed), as well as indicating the status of the system dump* (in
progress, complete, partial).
Notes:
A less well known use of the LED on rs/6000 / AIX systems is to run a daemon
known as loadavgLED, which takes the system load average (getloadavg(3)) from
the kernel and displays it to the diagnostic LED. Running this hack is nearly
certain to get the attention of any IBM rep, as normally it's
only lit up during bootup or something bad has happened.
Taking a system dump is the process of saving an image of virtual memory,
processor status etc for later forensic analysis. The AIX system dump
documentation (entitled "How to take a system dump") is quite amusing
reading, (possibly inspired by the context that tech support needs to convey
this faq to customers in a state of panic). See also deadbeef.