Older blog entries for acj (starting at number 1)

Last week I bought a Netgear WG511 wireless adapter for my laptop, intending to replace the archaic prism2-based adapter that didn't support WPA and barely worked. Initial searches indicated success in making it work with Linux, so I wasn't worried.

It turns out that there are at least three different versions of this card, each with a different chipset, and the only clear delineation is the "Made in X" label on the adapter, where X is either "China" or "Taiwan". My WG511 was made in China and has a Marvell chipset. Among other things, this means that I'm forced to use ndiswrapper and the Windows 2000 drivers. (The adapters made in Taiwan are natively supported by the prism54 driver included with the Linux kernel.) Okay, fine, I thought. It's not ideal, but the adapter is popular enough that maybe development of a native Marvell driver is underway.

The next step was to get WPA working. The NetworkManager applet listed my ESSID with good signal strength, but after repeated unsuccessful attempts to associate it was clear that something was wrong. The applet would spin for a few seconds trying to connect before immediately returning to the "no connection" icon. I tried the Windows XP drivers with the same result. I tried rebooting to give the card a chance to reset: same result.

The solution was to use wpasupplicant directly, specifying my ESSID, pre-shared key, algorithms, and so on directly in the wpa_supplicant.conf. After a few seconds of key negotiation, I was associated and had acquired an IP address.

So:

  • Manufacturers need to play ball more. Openness will sell more units!
  • What exactly is causing nm-applet to fail?
  • Yay for SoC hacking on the front porch.

This summer, I'm working on DebGraph (for Debian, as part of GSoC) with Robert Lemmen. Below is a brief description of where we're headed.

DebGraph is a tool that provides a simple, intuitive interface to the Debian package graph. The package graph contains information about packages (name, version, description, etc), their dependencies, and other useful details. By providing an easy way to interact with this graph, DebGraph enables useful analyses that can identify interesting or problematic constellations.

As an example, it is helpful for the Debian QA team to track cyclic dependencies (that is, packages that [in]directly depend on themselves). Such dependency cycles can be symptoms of package problems, and therefore it is important that there is tool support for locating and tracking them.

To date, many tools have been written to perform various tasks that involve analyzing Debian packages. The `lintian' tool performs tests on packages to ensure that they are complete. `Britney', another package analysis tool, assists the release and quality assurance teams by verifying package dependencies before promoting packages from the `unstable' distribution to `testing'.

As the number of packages in Debian has grown, the complexity of the package dependency graph has become difficult to manage. Development of new scripts that interact with package information involves addressing that complexity. This involves writing code that can represent the graph in memory and manipulate it, and such work is typically delicate and error-prone. It would be helpful to separate this functionality into a library that could provide generic graph infrastructure to anyone who needs to query or manipulate the Debian package dependency graph.

DebGraph aims to provide this generic infrastructure through a set of graph operators (e.g., union, intersection, find-cycles, and so on) that can be composed in complex ways to facilitate powerful analysis of the graph. In addition, the development of a functional query language will enable graph queries from domain-specific languages, thus removing the constraint of using C++ code to perform queries.

This work relieves developers of the burden of duplicating graph-specific code when developing new tools (or extending existing ones) that need access to the package dependency graph. By providing a generic infrastructure to support such tools, DebGraph enables tool developers (and others in the community) to focus on the issue at hand without becoming swamped with low-level details.

New Advogato Features

New HTML Parser: The long-awaited libxml2 based HTML parser code is live. It needs further work but already handles most markup better than the original parser.

Keep up with the latest Advogato features by reading the Advogato status blog.

If you're a C programmer with some spare time, take a look at the mod_virgule project page and help us with one of the tasks on the ToDo list!