An external programmer would be connected to some black box though, right? I mean, how do you know the interface the programmer is writing through isn't compromised inside the CPU?

I'm not trying to be pedantic; I'm simply unsure that the original comment of "The best part of POWER8 is the ability to flash and verify the CPU firmware using a completely open toolchain." and "[For Intel and others] you can't ever be sure what is running on them internally."

How does one know that with POWER8 the same isn't true? Just because you think you can flash it "directly" doesn't seem good enough to warrant that statement.

(Disclaimer: I have connections to both processors; my opinion on which is "better" or "more open" or "less likely to be compromised" is not stated here, and should not be inferred from this discussion. I'm merely trying to point out that I don't think the original comment's assertion is backed up by the reasoning it presented)

> I mean, how do you know the interface the programmer is writing through isn't compromised inside the CPU?

Inside which part? I suppose if you're worried about compromises inside the casing, you need to take off the heat spreader and look for yourself.

Anything on-die falls under the custom fabrications exception.

Forget custom fabrication; how does one know the real, official fabrication isn't compromised? I mean, the original comment was comparing the openness of POWER8 to the closeness of other processors, using only the ability to flash it openly as evidence, but if one is worried about other processors delivering compromised processors, why isn't one also worried about POWER8 delivering a compromised processor?

I guess I don't understand how that's an argument to support "one can't ever be sure what is running on [the others] internally", unless you manufactured the processor yourself from the open design.