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Archive for July, 2009

Why I Miss Command-Line Programming

July 12th, 2009

Here is the HTML I’m rendering:


<?xml version=”1.0″ encoding=”utf-8″?><!DOCTYPE html PUBLIC ‘-//W3C//DTD XHTML 1.0 Strict//EN’ ‘http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd’><html xmlns=”http://www.w3.org/1999/xhtml”>
<head>
<title>Software Carpentry: Computational Complexity</title>
<meta name=”author” content=”Greg Wilson” />
<meta name=”company” content=”Third Bit” />
<meta name=”date” content=”Sun Jul 12 17:32:26 2009″ />
<link rel=”stylesheet” href=”format/style.css” type=”text/css” />
</head>
<body>
<ul>
<li>Well-developed mathematical notation.</li>
<li>For any functions f,g : &#x2115; &rarr; &#x211D;<sup>+</sup>, write f &#x2208; O(g) to represent &quot;f grows on the order of g&quot;.</li>
<li>Mathematically: f(n) &le; cg(n) for all n &ge; B, for constants c and B.</li>
<li>Intuition: f grows <em>no faster</em> than g, to within a constant factor and ignoring any finite number of exceptions.</li>
<li>For example, 2n+7 &#x2208; O(n) because 2n+7 &le; 2n+7n = 9n for all n &ge; 1
<ul>
<li>But also 2n+7 &#x2208; O(n<sup>2</sup>) and 2n+7 &#x2208; O(2<sup>n</sup>), <em>etc</em>.</li>
<li>However, 2n+2 &notin; O(1).</li>
</ul>
</li>
</ul>
</body>
</html>


Here is the appearance with Firefox 3 on Windows XP:
ff31
And here is the appearance with IE7 on the same platform:

ie71

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Software Carpentry Starts Tomorrow

July 12th, 2009

The next run of the Software Carpentry course starts tomorrow (July 13), and as always, I wish a lot of things were in better shape. We’re using Skype to videoconference the lectures from Toronto to Edmonton and vice versa because everything else was either too broken or too expensive. The video quality is pretty poor, and nothing’s being recorded, but it’s the best we could do in the time we had.

Similarly, the notes are still in scroll format because there wasn’t time to debug the Javascript+CSS package I was trying to use to lay them out as slides, or to figure out how to get Firefox and IE to display things the same way. At the same time, I’ve just found out that Firefox puts two or three blank lines’ worth of vertical space around bullet items that contain math characters, while IE 7 doesn’t show them at all. Using raw character codes like &#x2208; instead of (supposedly standard) abbreviations like &setin; doesn’t fix the latter problem, and since I have no idea what might fix the former, I’m just going to shrug, file a ticket, and move on.

Most depressingly, almost none of the content has been updated. Doing this was #1 on my to-do list back in April, but it turned out that being #1 takes second place to things like booking rooms and making sure there’s a working projector.

Things are going much better with Basie (the Django-based rewrite of DrProject that we’re hoping will grow up to be a replacement for Trac). Feature freeze happened two days ago, and while a couple of key components still need some real development work, almost everything else is more or less working. There are still seven weeks left in the summer, so barring outright disaster, we’re on track to have a working system to use this fall.

The other summer projects have been making good progress as well—if you’d like to know more, check out their blogs:

They all plan to do demos on the morning of Wednesday, July 28, and you’d all be welcome—stay tuned for details.

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Goodbye, Pages

July 9th, 2009

Pages books on Queen Street West has announced it will close on its 30th anniversary due to the hike in rents at the city-owned property. It was a much-needed haven for me in some difficult years—no matter how bad other things got, there was always something on their shelves to distract me.

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Leigh Honeywell on Vulnerability Disclosure in Open Source Projects

July 6th, 2009

Leigh Honeywell (of HackLab phame) gave a talk to our students a couple of weeks about vulnerability disclosure in open source projects. It’s a nice introductory summary; hope you find it as useful as we did. (Note: some ISPs intermittently report “no such host” when trying to connect to her hypatia.ca domain, for reasons that are being investigated.)

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