Installing Django on EC2 & EBS

Posted on November 14, 2008 by MXH

This is a quick guide to setting up an Amazon EC2 instance as a Django server. There are many other guides along these lines, but this one includes a “turn-key” script to get everything up and running, as well as an implementation of the “polling” example from the Django tutorial.

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Scripting Windows

Posted on November 7, 2008 by MXH

If you want to write scripts for Windows, you have some unattractive options. You can use the DOS batch-file scripting language, but that’s a little on the primitive side. You can learn PowerShell (Monad), a typically overwrought, idiosyncratic MSFT affair. Or, you can pursue a better option: you can use JavaScript to script Windows.

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Isometric Graphics w/JS & HTML

Posted on October 31, 2008 by MXH

As an experiment, I decided to see if I could approximate a Flash game in JavaScript and HTML (without using the non-standard CANVAS tag). It turns out to be pretty easy to replicate an isometric display using some simple 2D graphics techniques.

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Extracting bitmaps from Flash

Posted on October 24, 2008 by MXH

Flash content is pretty common on the Web, but it is considerably less transparent than traditional HTML-based content. Whereas HTML-based content is built from human-readable script files and URL resource definitions, Flash content is locked inside a binary file format. It is sometimes necessary to convert Flash content into a more managable form. As an example of such a conversion, I discuss the process of extracting all JPEG images from a Flash (SWF) file, and present some Python code which performs the extraction.

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Quickie – Pythonic “if” statements

Posted on October 18, 2008 by MXH

In reference to my previous post, a reader writes:

You don’t need parens around your if conditions in Python – and it’s more Pythonic not to have them…


if size <= 0:
    return ""

Both statements are true. As an old C hack (and current heavy JS user) "if" statements Just Don't Look Right to me w/o the enclosing parens. Therefore, I thought the reader's point bore repeating.

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File-like Strings in Python

Posted on October 17, 2008 by MXH

Sometimes one has data stored in a string, and wishes to pass that data to a function that expects a file-like object. Writing the data to a file, then opening that file and passing it to the function is cumbersome and seems inefficient. A better solution is to turn the string into a file-like object, and pass it directly to the function.

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EC2 Instance Performance

Posted on October 10, 2008 by MXH

I’ve been working with a large-ish MySQL table on an EC2 instance. This table has approximately 147MM rows, and I’ve been disappointed with the performance I’ve seen. I took a look at how much performance I could gain by moving to a more powerful EC2 instance, and the answer is “some, but not all upgrades are equal”.

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Command Line Quickies

Posted on October 3, 2008 by MXH

One of the best things about working in the UNIX environment is the powerful command-line interface, which includes the available shells, scripting languages, standard utilities, and facilities for I/O manipulation. The strength of this interface is its modularity; a large-ish collection of powerful, somewhat single-minded tools is more flexible than a monolithic, “kitchen-sink” approach to interface design. However, this very modularity can make it hard to learn how to use the interface, since most documentation is devoted to a single tool or utility, and there is relatively little guidance on how the interface as a whole may be used to do work. Therefore, I present some simple UNIX shell commands, with brief explanantions, that might prove suggestive.

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Configuring EC2

Posted on September 26, 2008 by MXH

As I work with Amazon EC2, I find that I need to configure machine images for specific tasks. In general, I’ve preferred to perform this configuration by running brief install scripts on the standard Amazon-owned images, rather than using more complex, pre-configured images. For me, the core issues are those of transparency and trust.

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Lehman, Merrill, and Electricity

Posted on September 19, 2008 by MXH

Lehman Brothers and Merrill Lynch have been much in the news lately. In light of Lehman’s bankruptcy and Merrill’s sale to Bank of America, I thought it would be interesting to look at their participation in the electricity market. Merrill Lynch appears to have been a major player in that market, while Lehman, despite growing aggressively over the last two years, was not.

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