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Admiral Grace Hopper Explains the Nanosecond (1983) [video]

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93 points by zack6849 6 years ago · 15 comments

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jihadjihad 6 years ago

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

simonebrunozzi 6 years ago

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

She was a genius. Was a great character.

  • jkinudsjknds 6 years ago

    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 6 years ago

      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.

    • metiscus 6 years ago

      Safety critical hard-realtime systems come to mind as an example.

ncmncm 6 years ago

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.

jgrahamc 6 years ago

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

dls2016 6 years ago

She brought some nanoseconds to Letterman: https://www.dailymotion.com/video/x35dsz7

jki275 6 years ago

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

  • zack6849OP 6 years ago

    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.

nayuki 6 years ago

What year was this filmed in?

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