Ben's Bits

This summer I decided to explore a bit more about packet radio. You know, transmitting small amounts of information over amateur radio frequencies at very slow speeds. Prior to the advent of fairly ubiquitous high speed Internet connections this was a popular way for hams to move around information related to their activities. As it turns out the need for a dedicated packet modem (TNC) has gone away and the functionality can now be replaced with software and a sound card. One of my specific interests though was in learning about and improving the APRS system in the Twin Cities which allows people to automatically send GPS position information along with remote weather station packets and a variety of other small pieces of data. As it turns out APRS data can also be sent and received with a soundcard attached to a radio, forgoing the TNC and reducing the barrier to entry.

The primary program for soundcard TNC emulation is a free program called AGWPE and my first task was to learn how to setup and configure it as some of my firends had tried and failed to get it working in the past. Thanks to the great resources on the Internet I came upon the website of KC2RLM which contained excellent instructions for setting up and using the AGWPE program as well as a number of applications which would interact with the software.

Once I had gotten the basic soundcard TNC software up and running the next step was to start experimenting with APRS software. I tried lots of software including the common UI-View32 software but found the easiest to use and most modern software to be AGWTracker, a trialware program by the maker of AGWPE which supports all kinds of map layers such as Google Maps, MapPoint, etc. greatly improving the user experience. Of course, if you want to send updates back to the APRS-IS Internet network you need a password to go along with your callsign. As it turns out the password is a simple hashing algorithm designed just to prevent non-hams for injecting data into the network and is a documented algorithm. You can get your own APRS password or learn more about the algorithm at the APRS Password Generator website.

I'm not one who really enjoys writing code. In fact, I tend to avoid it whenever possible as it's just not that interesting to me. That said from time to time I have projects to complete where no existing software quite meets my needs and writing my own makes the most sense. This summer I was in the midst of collecting information and publishing a large extended family directory.

Clearly, the best way to do this is to store the data in a database. Because relational databases are most prevalent, I already have quite a bit of experience with MySQL and I knew I wanted to eventually make the data available via a PHP web application I decided to go with a MySQL backend. The trick here is that families aren't as relational as you might originally think. Families are really hierarchical data (parents, children, grandchildren, etc.) and relational databases have a hard time storing and recalling things based on these types of relationships. For example, a typical family query might be one for a list of all descendants of someone. As it turns out families aren't the only hierarchical data people might try to store in a relational database. Any business database which shows managers and reporting personnel is also a hierarchical data set albeit usually with fewer levels and much less complication (no need to track divorces, remarriages, spouses, etc.)

I was able to find and read up on several methods for storing the relational information but the one I ended up using is that proposed by Rob Volk of SQLTeam where the expensive (computationally) hierarchical relationships are stored in two additional fields for each record (depth and lineage) with parseable separators between generations. The database is initially loaded through a series of several (expensive) recursive queries but then can be maintained through triggers when information is added or updated.

In addition to my technical interests I'm involved in many other things including music. Great advances have been made in the integration of music and computers in the last 20 years. As with many other industries, computers have changed the way music is created, disseminated and recorded. One of the many areas where computers have been used is in the typesetting of sheet music. This has allowed for major music publishers to reduce costs and composers, arrangers and musicians to widely disseminate music without the need for an engraver and publisher.

Like many advances the transition from hand engraved music scores to computer typeset scores has not been without problems. Most notably computer typeset music can be harder to read and interpret by musicians and simply doesn't look as musical or beautiful as hand engraved music. LilyPond has an excellent and illustrative essay on the problems of computerized engraving which I encourage you to read.

The Finale program by Make Music (formerly Coda Music) and Sibleus by Avid are undoubtedly the biggest players in the music notation software field but both suffer from the problems of automated engraving (lacking life, more difficult to read and interpret, etc.) but what is a composer/arranger to do? Assuming you can't afford to hire a professional hand engraver (if you can even still find one) the answer is quite clear actually. Lamenting the decline of music score quality a group of developer/musicians got together and wrote a software program called LilyPond. When used correctly this program produces some of the most beautifully engraved music you can find. Best of all the program is free and open-source meaning that anyone can see the code that is used to generate the music and contribute fixes and enhancements. The program is cross-platform and can work on Linux, Macintosh OSX and Windows (though Linux and Macintosh are admittedly easier to get running).

As it turns out there is a bit of a catch though... While programs like Finale and Sibleus offer a graphical notation editor, LilyPond is a specialized program which does nothing more than automatic engraving (typesetting) based on a textual input file. This means to use LilyPond you need to learn how to manually describe the music in the LilyPond formatted text file, a significant impediment for many composers/arrangers. Or do you?

Recently there has been quite a bit of movement on developing some free and open source music notation programs, many of which support exporting to the LilyPond format. While the exported LilyPond file may still need some manual tweaking to get the best possible score it's certainly much easier than entering an entire score into LilyPond format by hand.

One of the oldest and best known LilyPond compatible editors is NtEd (of NoteEdit lineage) by J. Anders. Though not immediately apparent from the feature list, this Linux software supports exporting to LilyPond. A more recent entrant to the music notation space is Denemo, a multi-platform WYSIWYG notation editor designed specifically for LilyPond. Finally, one of the most promising solutions seems to be MuseScore, a project stemming from the MusE Midi/Audio sequencer. MuseScore looks to be one of the most consumer friendly options with packages for Linux, Macintosh and Windows readily available and a fairly decent engraving engine itself as well as LilyPond support.

Last week I served as a guest panelist for This Week in Law (aka TWiL) and Episode 20 is now available for download. I think it's a pretty good episode so if you're at all interested in the legal challenges of dealing with technology I hope you'll give it a listen. I had a great time with my fellow panelists Evan Brown, Colette Vogele, Ernie Svenson and host Denise Howell recording this episode.

The discussion points are available at delicious. We discussed several contemporary topics including the debate about iPodMeister which trades you an iPod for all your used CDs while still giving you a copy of all your music ripped from the CDs, the appropriate use of social networking, Obama's Blackberry, P2P networks and the decline of the recording industry, as well as many more topics. I think it's worth a listen but don't take my word for it, check it out yourself at TWiT.tv/twil20.

There are many technologies which I am very much on top of because I use them on a regular basis, here are others that I interact with periodically and it's enough to stay abreast of developments and do basic troubleshooting but from time to time there are technologies that I'm only peripherally aware of and have only a basic understanding of. One such technology is virtualization or virtual machine software.

For almost ten years I've been hearing about software like that made by VMware which allows for a virtual computer to run inside of a host operating system. To this day I haven't done anything more with this type of software than to fire it up and see that indeed it does work. It's not that I don't see the advantages, it's just that I haven't personally encountered a situation where I can justify the time and effort it would take to set it up. That said I do like to know what's going on in all areas of technology and what I've been hearing lately is some movement in the open source virtualization arena.

For some years now I've known about some projects such as Xen, Bochs and QEMU. The problem with these solutions is they are really not open source replacements for commercial virtual machine software like VMware. I've heard great things about Xen and it's ability to virtualize Linux systems (on Linux systems). While this is valuable in many cases it's not for most of what I want to do which is to run a guest OS on an entirely different host OS. Bochs is more on target but this is an effort to emulate the x86 platform enitrely in software, a bit heavy duty (and with significant speed costs) for what I normally would want to do which would be to run an x86 guest OS on an x86 host, for example a Windows guest on a Linux host. QEMU has the upper hand here. While it's still a big heavy emulator there is some closed source accelerator code which can help in x86 on x86 situations. Of course the closed source part is a bit of a drag. Still the real problem with all of these is that they are incredibly more difficult to configure (and especially to configure and setup a new guest OS on) than their commercial counterparts.

Well, the world may be changing. What I've been hearing recently is that an open source project from Sun called VirtualBox is looking like it will give some of the commercial vendors a run for their money (so to speak). There is no doubt that VirtualBox is still in the early stages of life but the development team seems to be putting some real effort into it and new releases have been timely. I'll be excited to follow the continual development of this product.