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Comment by hettygreen | Hacker News Reader

What were the LED's indicating?

Replying to myself here - I decided to just actually go read wikipedia about this. Here's the answer:

<quote>

By default, when a processor is executing an instruction, its LED is on. In a SIMD program, the goal is to have as many processors as possible working the program at the same time – indicated by having all LEDs being steady on. Those unfamiliar with the use of the LEDs wanted to see the LEDs blink – or even spell out messages to visitors. The result is that finished programs often have superfluous operations to blink the LEDs.

</quote>

I love that, makes me want to build an analog PC and stuff. Or visualizers for system activity.

Yes I'd unironically watch defrag work.

That's a lovely unintended side effect of incentives :P

There is no documentation of what the LEDs were _actually_ doing. There are descriptions, like 'Random and Pleasing is an LFSR', but no actual information that maps to actual pixel coordinates spaced in time. Nearly zero code.

I'm saying this because I need this information, and the fastest way to get information is to state that it's impossible or doesn't exist.

Seems like CM-1 and CM-2 show CPU activity, so each light blinked when a CPU did something. Those were the ones that were designed by Tamiko Thiel.

Then, CM-5 did have the option of having "artistic" or "random patterns" on it, apparently designed or co-designed by Maya Lin. IIRC, the CM-5 is the one appearing in Jurassic Park.

I don't know if is there any firmware code or hardware design available to check how that function worked. Maybe the people from the Computer History Museum knows something. They have the first CM-1 and have at least one CM-5.

Check their library to see if maybe some of the technical docs say something:

https://www.computerhistory.org/collections/catalog/search-c...

I would also like to obtain this information that clearly doesn't exist. Please reply to my comment to prove me wrong.

Depended on what was running.

As a developer you had explicit access to them, so you could use them for debugging. A lot of times, they were just running an RNG to look cool though.

Blinkenlights

Amusing this downgraded when it points directly to the word used for the phenomenon: https://en.wikipedia.org/wiki/Blinkenlights

I seem to recall an intel i960 was used to drive leds on at least one model.

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