Reflecting on a New Computer

By Charles Sutton on August 11, 2012

Presently I am still enjoying the honeymoon phase of my new laptop. To avoid the slightest appearance of ostentation, I will refrain from going into details of exactly what laptop I got, except to say that it is of course a Mac, and it’s REALLY REALLY cool!

Apple provides a Migration Assistant that apparently will copy all of your files and settings from your old computer, so that your new Mac looks exactly like your old one. My feeling about this is: Why would anyone want that? For me, one of the pleasures of a new computer is that it’s *clean*, unburdened with hundreds of files scattered around my home directory that I never use but are too important (or too numerous) to simply delete.

So for years, whenever I get a new computer, I never copy my files over en masse. Instead, I copy over a small set of files that I know I need, and leave the rest on a backup. Then the next day, I find that I need a file on the backup that I didn’t realize, go back and copy this over, etc.

This process stabilizes after a week or so, and my electronic life feels much less cluttered.

I suppose that I could just blow away my home directory every year for the same feeling, but somehow it is hard to convince myself to do this.

I wish that I could use the same process for physical papers, but sadly paper information cannot be stored as compactly as its electronic equivalent.

Super-Mac-Geek-Alert: For several years, I have been using Keychain to store secure notes such as password hints for bank logins, etc. I thought I was very clever to avoid impressive but costly tools like 1Password. Then I tried to copy the Keychain to my new computer. Painful. I think from now on I’ll keep these notes on a small encrypted disk image.

Converting Fahrenheit into Celsius... The Smart Way

By Charles Sutton on August 3, 2012

or, from small beginnings…

One of the minor challenges of moving from the US to the UK is temperature. People in the UK always discuss the weather, and when they do, they use Celsius. My brain still works in Fahrenheit, so I need to convert typical daily outdoor temperatures in my head, and quickly enough that I can carry on a conversation.

You probably learned a formula in school for doing this. Completely useless. Forget all about it—but you already have, haven’t you? You might remember, if you’re clever, that the formula involves 9, 5, and 32 in some combination. But is it 9/5 or 5/9? Do you add 32, or do you subtract it? And do you do that before or after you multiply? And now people are wondering why you’ve been staring at them for two minutes when all they asked is how hot it was when you were in Seattle last week.

The problem is that the equation to convert C to F is too similar to the equation for the reverse, and both equations are too difficult to compute mentally. What we need is a simpler equation, that is easy to remember, and easy to work out quickly in your head.

So here’s the trick. You memorise the following correspondences:

0 °C = 32 °F
10 °C = 50 °F
20 °C = 68 °F
30 °C = 86 °F

Then, to convert any temperature that is near these, approximate 1 °C = 2 °F. This will allow you to convert almost any naturally occurring outdoor temperature in the UK in either direction to within 1° accuracy.

Let’s try it. As I write the current temperature in Edinburgh is 14 °C. This is 10 °C plus 4° extra. From memory convert the 10 °C to 50 °F. Then convert 4 °C extra to 8 °F extra and add it back on. This gives you 14°C = 58°F. This is not exact, but close enough that you know to wear a jumper. The exact formula is

  14 * 9 / 5 + 32 = 57 F

Good luck doing that in your head.

It tickles me that (maths alert) this is a piecewise linear approximation to a linear function. Mathematically, you would have to believe that a piecewise linear function would be more complicated, but mentally, it’s not. Maybe there’s a deep psychological principle here that scientists will figure out someday.

Until then, quite chilly today, isn’t it?

Tags: expat