8.1. What are the LED's left side of the machine for?
This is from John Milton's HwNotes series #1.
0 RED: This is the "user LED". It can be turned on and off
with the syslocal(2) call. It is not used by any
1 GREEN: This is the one most people get wrong. This LED
toggles every time there is a process context
change, and is cleared on the whole second.
2 YELLOW: This is the idle LED. When it is on, there are no
processes in the ready to run state.
3 RED: Heart beat LED. This is toggled on the whole second.
This and other interesting information is available in the
HwNote series 1-15 that are archived on OSU.
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