I love discovering new tools.
Lately my work on Ubuntu Linux kernels has had me paying closer attention to the Intel open source graphics drivers.
I’ve come across a few tools that are handy to developers and people with more advanced troubleshooting skills. One of those is intel_reg_dumper, which (not surprisingly) dumps the values of a whole bunch of internal registers from the graphics card. This comes as part of the xserver-xorg-video-intel-dbg package.
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On November 6th I’ll be helping Dave Freese, W1HKJ make a presentation about fldigi to the Huntsville Amateur Radio Club. Fldigi is an amazing open-source cross platform application for communicating using sound card digital modes on amateur radio.
Dave is really knowledgeable about the encoding and error correction used for the various modes, and I learned a lot by helping him with a similar presentation at the Huntsville Hamfest this year. Our demo was cross-platform between Windows and Ubuntu Linux.
There are some really interesting uses being made of fldigi and some companion applications - sending digital files error-free by amateur radio. This is useful for emergency communications in post-disaster situations, when information must be accurately transmitted. Some of these applications do not use point-to-point connections, and therefore allow a file to be received by multiple stations at once. That way, if any station fails to receive the file correctly, they can get a “fill” from any other station who did get it.
It’s possible to perform these file transfers simply by holding the microphone on an FM radio near the computer speaker, and to receive them with a computer microphone near the receiver!
This should be a worthwhile presentation for people with any level of interest or experience in digital sound card modes. For more information see Dave’s excellent web site. Don’t miss his sights and sounds of digital modes page, especially if you’ve been listening to the sounds on the ham bands and wondering what modes they are.
The presentation will be November 6th at 7:30 at the American Red Cross chapter house, 1101 Washington street, Huntsville, AL. This is the regular weekly meeting place and time of the Huntsville Amateur Radio Club.
PPAs on Launchpad are an amazing way to get the latest crack builds, which is useful if you track or contribute to an upstream project, or test new code to see if it resolves a problem. That’s what I’ve been doing this week - I installed the latest Xorg crack on top of a karmic beta install.
If you visit that last link, you’ll find a description of how to install and use a package called ppa-purge, which will revert the PPA settings and restore the packages to the distro versions. This makes it much easier to restore the system, or even to bounce between the distro and bleeding edge versions and see what changed.
Dave Freese, W1HKJ will be presenting a forum at the Huntsville Hamfest titled “Emergency Communications using HF Digital Modes”. Dave and a core group of contributors have been working for the last few years on a suite of open source applications for amateur radio. The fldigi application is the flagship of these.
Fldigi is a digital modem application which generates and decodes a number of digital modes using the sound hardware in your computer. Amateur radio using digital modes has been growing in popularity, and with good reason. These modes offer a variety of tradeoffs between rf bandwidth, data bitrate, error correction, and noise immunity.
These modes are all sent and received using audio frequencies that fall in the normal voice range used in amateur radio, about 300-3000 Hz. Some modes use very little bandwith, as low as 31Hz, allowing many contacts to take place within a frequency range that would be occupied by one voice contact. These modes are most commonly used with a text interface that resembles internet chat, but are also suitable for inclusion in a higher layer of protocol which allows further error correction, block sending, and retries. When used with a ‘stack’ like this, it is possible to send binary files over amateur radio error-free. This is useful for emergency communications. An example is to be able to send a spreadsheet listing items needed at a shelter, instead of reading and copying every line in the document by voice. The low speeds of these modes limit the usefulness to relatively small files, but a lot of information can be passed in small text files.
Fldigi runs on Linux, Free BSD, Windows XP, W2K, Vista, and OS X. At the hamfest, Dave will be demonstrating using windows and a Linux platform, and I will be helping him demo with my Ubuntu system.
The forum is at the Huntsville Hamfest from 14:00-16:00 on Saturday August 15th, in Salon 10. For more information about these apps, see Dave’s site
I’ll be presenting a session at Atlanta Linux Fest titled “Debugging the Kernel”. This presentation originated with Colin King, another member of the Ubuntu kernel team. Colin’s blog has a wealth of debugging information.
The presentation is an overview of various methods used, as applied to increasing difficulty. What can you do when you have no video, no console, no serial ports, and no network? Come find out.
I’ve committed to write a monthly article for our amateur radio club newsletter on Linux and amateur radio. I’ll be posting them here also. The first one is an introduction to how to run linux from a live CD or to install it.
I’d like to expand this so that I’m writing more often here, and then consolidating those pices for the newsletter, and also take the chance to get more information into the Ubuntu wiki pages for amateur radio.
