Tuesday, 24 March 2009

In honour of Ada Lovelace Day, a post about Grace Hopper

I know I should blog about Ada Lovelace today, in honour of Ada Lovelace day. But I've actually always been more of a fan of Grace Hopper.

Here's why:

When I was just a wee girl my Dad bought a computer. My brother and I started writing little programs for it in BASIC and Dad thought that was pretty cool. To encourage me to keep it up, he told me a story about a lady long ago (ie, before I was born) who had been one of the very first computer programmers, and since he was an electronics engineer he told me his favourite story about her: the visible nanosecond.

Computer scientists are pretty fond of analogies. Car analogies, usually, but anything will do. The reason for this is that so much of what we do is in our heads, intangible, can't be touched or smelt or seen. I use analogies all the time. Admiral Grace Hopper, came up with a beauty: a wire "one nanosecond" long. She got a real wire, and worked out how far electricity could flow along it in a nanosecond, and chopped it off to that length - about a foot. A coil of wire nearly a thousand feet long became a microsecond. A speck of pepper became a picosecond.

A bit of tutuing around in Excel tells me that the exact length of that nanosecond-wire was 29.98cm. The microsecond wire was 299.8 metres long, and a length of wire one second long would be 299,792,450m - which would wrap nearly 7.5 times around the Earth.

I think she chose the right fraction of a second to make into wire.

Admiral Hopper did other cool things too, which had a more significant effect on the world and on me. She pretty much invented compilers in the 1950s, for example, which made it possible to program computers in something sort of like English, which in turn made it possible for a nine-year-old girl in Auckland to learn BASIC in the 1980s and wind up in IT in the 21st century.

She's also credited with my favourite axiom: "It's easier to ask forgiveness than it is to get permission."

More detail here and here . Tell your daughters.

Wednesday, 11 March 2009

Quite possibly the most inappropriate new hobby

... for someone who is forever going on about reducing her CO2 emissions, is ... drum roll....

... learning to fly.

First theory lesson was tonight. We're doing Meteorology first, so we started with the hard stuff - Environmental Lapse Rate, Dry and Saturated Adiabatic Lapse Rates, and Dew Point and Relative Humidity, and how some jiggery pokery with all of them tells you how high up the clouds are going to form and how unstable the weather's going to be.

The Met theory book (Weather to Fly, hur hur) is about a centimetre thick, and has lots of juicy graphs and charts. I'm already geeking out on it a bit... I like that feeling when something which was previously gobbledygook to me becomes sense. Like this (a Creative Commons image):

There are six of us in the class - me, Dad (hi Dad!), Alan who didn't say anything at all, Ryan who is about fifteen and had to leave early because he's still on his restricted drivers' licence, Matt who is Australian and has already done the Law module and is looking for a plane to buy, and Sina who didn't say anything either. I hope we get a bit more discussion later.

I also proved (yet again) that I suck at navigation; missed the offramp on the way out, and two turns on the way home. Can't wait to see how bad I am when I'm navigating in 3D rather than 2D.

Must book a practical lesson soon. Go see these cloud formations for myself.