Grace Hopper on nanoseconds

Love it! Watching the video on You Tube I noticed other videos on the side including Lady Gaga on Letterman. Couldn't help but think Grace Hopper is the kind of person who should be famous and a role model. Instead its people like Lady Gaga.

johansch• 14 years ago

After reading a bit more on Grace Hopper, particularly about the first ever (?) compiler "A-0" she made, I found this in-depth article describing it (and a bit more):

http://www.cbi.umn.edu/iterations/norberg.html

tripzilch• 14 years ago

That first paragraph was as good as unreadable thanks to all the miles, gallons and Fahrenheits.

11.8 inch ... times about 2.5 is umm wait it's a link, maybe if I hover it, no they didn't put metric in the title tags either.

"In one millisecond, light travels 186 miles", which is about the same distance as a million squirrels put head-to-toe. Why not measure in squirrels? It makes about the same amount of sense, except that "one million" is a nice round number, unlike "186".

lutorm2• 14 years ago

I don't endorse inches as a measure, but they are pretty intuitive. Maybe it's because the swedish word for inch is "tum", which means "thumb". And it happens to be 1.25 inches from the top of my thumb to the first joint.

DasIch• 14 years ago

Metric units aren't any less intuitive when you are used to them.

Someone• 14 years ago

An inch is (supposedly) measured as the _width_ of the upper phalange of the thumb, not as its length.

And 'thumb' is its name in Dutch and French, too.

DanBC2• 14 years ago

It's disappointing that they didn't also include metric; or do metric first with Imperial for the US and Burmese audience.

The distance travelled by light in 1 ns, = 299.792458 mm (11.803~ in).

yew• 14 years ago

I suspect they used US customary units because that's what's used in the video.

Anyway, if we're only going to talk about readability then I'll note that the text is imminently comprehensible to anyone with an intuitive grasp of said units. So the real question is one of functionality. (I'll put my vote in for metric, of course.)

DanBC2• 14 years ago

For people using A4 paper: The long side of A4 is 297 mm. So one billion bits of A4 (plus another one billion bits of 2.792458 mm) are how far light travels in one second.

alex_c• 14 years ago

186 miles is 11,784,960 inches, and an Eastern Gray Squirrel is 9-12 inches.

I'm impressed, did you actually make the calculation first?

Dylan16807• 14 years ago

It would have been fine if they had rounded it slightly more to 1 foot. If you don't know how long a foot is, well it's about as long as your foot.

Jun82• 14 years ago

On a tangential note, here's something useful for back of the envelope calculations: a billion seconds is \pi centuries.

jgw• 14 years ago

No, 1 billion seconds would be (around) π decades...

Jun82• 14 years ago

Oops, you're right, I got the \pi in the wrong side of the equation!

Evidently this is called Duff's Rule (http://www.johndcook.com/blog/2009/07/01/three-rules-of-thum...).

gwern• 14 years ago

I always enjoyed microcentury = ~53 minutes. Something to think about in class.

phaus2• 14 years ago

So far you guys have overlooked what was possibly her greatest contribution to humanity.

She was credited with coining the phrase "It is better to ask for forgiveness than to ask for permission."

In all seriousness, she was an amazing person. Whenever I hear someone start complaining that women shouldn't be allowed to pursue a career, I think of all of the things that we wouldn't have if it weren't for women like Grace Hopper.

Edit: Someone posted the quote before I finished writing. Good job!

enneff• 14 years ago

> Whenever I hear someone start complaining that women shouldn't be allowed to pursue a career...

Woah, where do you hear that?! Aren't we in 2012?

phaus2• 14 years ago

"The radical feminists succeeded in undermining the traditional family and convincing women that professional accomplishments are the key to happiness,"

-Rick Santorum

wiredfool• 14 years ago

I got one of her nanoseconds at a talk when I was in HS. It lived on my bulletin board for a good long time.

Not mentioned in the article, but in her talk (at the time anyway) was that a picosecond is about the size of a pepper flake. She had a packet of those, but they're less durable to give out.

gnosis• 14 years ago

Then there's the attosecond[1], during which time light can only travel the length of three hydrogen atoms, and is the shortest measured period of time.

These[2] other time intervals are also interesting.

[1] https://en.wikipedia.org/wiki/Attosecond

[2] https://en.wikipedia.org/wiki/Orders_of_magnitude_(time)

shabble2• 14 years ago

I can't view the video, so I'm not sure if it's straight up transcription error, or just confusion, but:

the length of wire that is as long as light can travel in one nanosecond. The length is a very portable 11.8 inches. A microseconds worth of wire is a still portable, but a much bulkier 984 feet.

<snip>

Understanding the profligate ways of programmers, she suggests that every programmer wear a necklace of a microseconds worth of wire

(Emph mine) I can see ~12" as a perfectly reasonable necklace length, but ~100 yards? Seems like a bit of a pain in the neck.

[Edit:] After a bit of playing around with Wolfram Alpha, it seems that a microsecond of AWG#40 copper would weigh only ~14 grams. But at 0.08mm, or around half the thickness of a hair, it's going to be a bit fragile.

Using a more reasonable #28 (0.3mm) wire comes in at 220g, which is definitely on the high side for a necklace.

And woe betide anyone using gold!

moreati• 14 years ago

> but ~100 yards? Seems like a bit of a pain in the neck.

That's the point - to serve as a constant reminder of how much circuit/processor time is thrown away for every microsecond it sits just waiting

shabble2• 14 years ago

There's a certain parallel to draw with the Iron Ring/Engineer's Ring[1,3].

Quoting from the latter article:

The Iron Ring is worn on the little finger ("pinky") of the working (dominant) hand; this would be the left hand for a left-handed person.[2] There, the facets act as a sharp reminder of one's obligation while the engineer works, because it could drag on the writing surface while the engineer is drawing or writing. This is particularly true of recently obligated engineers, whose rings bear sharp, unworn, facets

[1] https://en.wikipedia.org/wiki/Iron_Ring

[2] NMF

[3] https://en.wikipedia.org/wiki/Engineer%27s_Ring

saurik• 14 years ago

Watch the video: not only does she hold a microsecond of wire up (so you can see what it is like), but she actually recommends hanging it on the wall above you desk (and as a joke). She then furthers the joke with the comment about hanging it around the neck, and it is specifically funny because it would be unreasonably heavy.

Grace Hopper on nanoseconds

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