Author: Harvey

Inspired by this StackOverflow question, [“How do I sniff on a port for log messages using python?”][so_question], I decided to figure out how to capture and process packets in Python. It turns out to be quite easy once you work out the kinks. Except the kinks were a pain to determine.

[so_question]: http://stackoverflow.com/q/28870666/47078

Sample output:

$ sudo python capture.py
10:27:44.016601    hello ('127.0.0.1', 61129)
10:27:44.016614    hello ('127.0.0.1', 61129)
10:27:54.019731    hello ('127.0.0.1', 61137)
10:27:54.019741    hello ('127.0.0.1', 61137)

(more…)

In a [previous post], I compared the different methods for parsing XML in Qt. After a comment about XQuery’s performance, I [added some code] to test performance using a simple, but large (304MB) XML file. Times are sorted and normalized to the smallest value.

| Run Time | Method |
| :——: | :—————————————————- |
| 1 | XQmlStreamReader – processElementsByTagNameHierarchy – text() |
| 1.1 | XQmlStreamReader – processElementsByTagNameHierarchy |
| 1.1 | XQmlStreamReader – processElementsByTagName |
| 2.2 | QDomDocument |
| 4.0 | XQuery |

[previous post]: http://3gfp.com/2014/07/three-ways-to-parse-xml-in-qt/
[added some code]: https://github.com/sr105/international_trade/
(more…)

# Tramp #

I often find myself editing files in terminals on remote machines, and I really need to add [Tramp] to my muscle memory. Tramp is an Emacs package (installed by default?) for editing remote files via ssh. It allows you to open files with urls like this: `/ssh:user@host#port:/path/to/file`.

Note: I use `ssh` instead of `scp` (used in all of the examples) because the webpage says it’s faster and also because it supports the `#port` piece while `scp` does not. Also, the `user@` and `#port` pieces are optional. So feel free to use the minimum: `/ssh:host:/path/to/file`.

[Tramp]: http://www.emacswiki.org/emacs/TrampMode

(more…)

Have you ever re-formatted an SD card and noticed the performance degrade? You formatted it FAT32 just like it came from the factory, but it runs slower. Except you didn’t actually format it like the factory. The following is a document I wrote mid-2013 about formatting microSD cards with a single FAT32 partition with a layout that is optimized for speed and lifetime. It also includes details about using this card as a bootloader source for TI OMAP3/4 processors.

(more…)

I wanted to build the minimum set of adapters necessary to connect an RS-232 USB-to-Serial adapter to any other board with a DB-9 connector. It turns out that you only need two:

• Male-Female Null Adapter
• Female-Female Gender Changer

My son’s Boogie Board from Brookstone recently stopped working and I suspected that he had given it the stated 6 years of use in 2 years time. Unfortunately, Improv Electronics, the manufacturer, chose to save a few cents and used a soldered battery. I needed to solder something for my work, so I thought fixing his board might provide a dry run of my soldering skills before I ruin a customer’s hardware. (more…)

Something that was not obvious (to me) in the hgsubversion documentation is that you can clone any part of a subversion repository. (more…)

Update: Added optional code to show how you would put feature in a branch first rather than just committing directly to the trunk. (more…)

It’s like a broken record. It’s like a broken record. Here’s another example.