On 01/22/2017 07:26 PM, Hal Murray wrote:
Many years ago, I designed network gear. That was back when a controller was a board full of small and medium sized chips rather than a single big chip. I always put a few LEDs on the board wired up where the microcode could get at them. Most of the time they were just eye candy. But occasionally I would borrow one and hack the microcode so a LED would be interesting on a scope.
Ah, just like those status LEDs on PCBs, subsystems, and modules in properly-engineered equipment (both old and modern minicomputers, aerospace equipment, VME and VXI systems, some other servers [some of HP's small servers, at least, even feature a neat diagram on the front panel, with status LEDs indicating the status of key subsystems or components thereof], etc.) Apple's hardware obviously is an offender in this regard---I remember once having to service an iMac (or some other modern Apple PC), and I seriously could not figure out how to turn it on, and when I had to temporarily shut off the power distribution system, I could not figure out what the PC's power state was (to ensure a graceful shutdown of the system).
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