Re: Nvidia Replaces Intel on DOW

On Mon, 4 Nov 2024 11:29:47 -0800, John Ames wrote:

On Mon, 4 Nov 2024 18:58:09 -0000 (UTC)
Lawrence D'Oliveiro <ldo@nz.invalid> wrote:
 

i.e. "eighteen inches is a nanosecond" 

 
For suitably small definitions of “inch”, I suppose ...

 
Well damn, I was misremembering from accounts of Grace Hopper's famous
"nanosecond" wires. I guess another fundamental principle is "double-
check yer dang constants..." ;)

1 light-nanosecond is close enough to 12 inches, or almost exactly 30cm.
The speed of light is officially defined as 299 792 458 m/s exactly.

But remember, that’s for light or radio waves in a vacuum (or a close
enough approximation, like Earth’s atmosphere). Electrical signals through
a wire travel much slower -- I believe half the speed of light or even
less.

And the actual charge carriers (electrons, in a metal wire) move even
slower; I remember a book that said they can take several days to go
completely around an electrical circuit.

By the way, the speed of sound under normal Earth atmospheric conditions
is very close to 1 millionth of the speed of light. Coincidence? You be
the judge. ;)