Siemens SICOMP M80 frontpanel

The writing next to the LEDs reads, from left to right:

Power

Stop

Processor check

Memory check

Console check

Bootstrap check

Power supply check

Power supply

Upon booting, first the microprogram is load, then some CPU tests. If the system was brought down by force, i.e. major power outage, first the CPU commands are checked, then RAM, PROM, memory, cache, test if a console is attached, and then check for the bootstrap code. During this process, the according LEDs light up if the tests succeed.

(by the way: strange standarts.. 300 Bauds, 8 bits, odd parity, 1 or 2 stop bits for doing basic hardware checks using a video terminal...)