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Admiral Grace Hopper Explains the Nanosecond
- jki275 6y agoPosted pretty regularly here, it's a great talk. She was a true treasure to the CS world and to the Navy.
- zack6849 6y agoYeah, 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.
- simonebrunozzi 6y ago"So they know what they're throwing away when they're throwing away microseconds" She was a genius. Was a great character.
- jkinudsjknds 6y agoI 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.
- metiscus 6y agoSafety critical hard-realtime systems come to mind as an example.
- ncmncm 6y agoAnything 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.
- jkinudsjknds 6y agohmm... idk. This feels difficult to believe. I don't think my editing speed would suffer if you threw 100 additional microseconds of delay into font rendering. I feel any meaningful loss would need to be measured in milliseconds or longer. Typing tests don't really help here because you don't read what you type if you're competent. I don't know how I could test...
- jihadjihad 6y agoGreat 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
- nayuki 6y agoWhat year was this filmed in?
- DavidSJ 6y ago1993 it would appear: https://youtu.be/Sn0f0vpn8jE?t=7m50s https://youtu.be/Sn0f0vpn8jE?t=7m50s
- jgrahamc 6y agoBased 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
- dls2016 6y agoShe brought some nanoseconds to Letterman: https://www.dailymotion.com/video/x35dsz7 https://www.dailymotion.com/video/x35dsz7
- ncmncm 6y agoIt 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.