
Admiral Grace Hopper Explains the Nanosecond - zack6849
https://www.youtube.com/watch?v=9eyFDBPk4Yw
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jihadjihad
Great stuff. I'm reminded of the classic "we can't send an email over 500
miles!" which is somewhat related, and equally entertaining:
[http://web.mit.edu/jemorris/humor/500-miles](http://web.mit.edu/jemorris/humor/500-miles)

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simonebrunozzi
"So they know what they're throwing away when they're throwing away
microseconds"

She was a genius. Was a great character.

~~~
jkinudsjknds
I enjoyed listening to her, but I don't know if I understand her point here.
There was something intuitive about why certain processes require a large
number of nano seconds due to physics. But I have a tough time thinking of any
process besides financial trading that can't spare a microsecond.

~~~
ncmncm
Anything that you need to do a lot of, in a second, suffers for wasted
microseconds.

If your input processing and font rendering pathways waste microseconds (and
they do) it makes a delay in characters you type showing up on the screen, and
a corresponding, measurable reduction in your editing throughput.

When our machines were a thousand times slower, characters showed up on the
screen in substantially less time than they do today. The difference is mainly
a result of cumulative wasted microseconds, in so many places that nobody can
afford to gather them up.

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ncmncm
It is funny (to me anyway) that the nanosecond wires she used to give out take
rather more than a nanosecond to traverse.

The speed of signal propagation is largely determined by the density of the
wire's insulation, because the signal is an electromagnetic wave carried at
the skin of the conductor, with its electric field oscillating in the
insulation, so propagation is limited by properties of that. The distance
covered in a nanosecond is typically between seven and eight inches. In wires
with foam insulation (typically co-ax) signals go a little faster. In optical
fiber, a nanosecond is under seven inches, because the speed is determined by
the same property of the glass, which is denser.

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jgrahamc
Based on this I made downloadable and printable nanoseconds:
[https://blog.jgc.org/2012/10/a-downloadable-
nanosecond.html](https://blog.jgc.org/2012/10/a-downloadable-nanosecond.html)

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dls2016
She brought some nanoseconds to Letterman:
[https://www.dailymotion.com/video/x35dsz7](https://www.dailymotion.com/video/x35dsz7)

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jki275
Posted pretty regularly here, it's a great talk. She was a true treasure to
the CS world and to the Navy.

~~~
zack6849
Yeah, I wasn't sure how often this pops up, it came up in conversation and I'm
not familiar enough with HN to see when the last time it was posted, so I
figured i'd just post it and let it go unnoticed if it's been posted too often
recently.

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nayuki
What year was this filmed in?

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DavidSJ
1993 it would appear:

[https://youtu.be/Sn0f0vpn8jE?t=7m50s](https://youtu.be/Sn0f0vpn8jE?t=7m50s)

~~~
kingisaac
She died in 1992, so I highly doubt it was recorded in '93.

~~~
csixty4
She's the ghost in the machine.

(Given the quality of the video, I'd be inclined to think 1983 rather than
1993)

