Sunday, February 13, 2011

Gentoo's Reform and Future @ FOSDEM

For all those interested who could not make it to Brussels, the talk by Petteri, Roy, and Jorge on "Gentoo's Reform and Future" is now online at YouTube - or below. Cheers!

Tuesday, February 8, 2011

Most obscure e-mail of the year (so far)

I have the vague feeling that somehow this is out of my field of responsibilities.

From: xxx xxx <>
Date: Today 05:24:03
Spam Status: Spamassassin 0% probability of being spam.

Andreas K. Lord Huettel

gcam-2010.07.27.ebuild USD?




Sunday, February 6, 2011

Fries, FOSDEM, Delirium Tremens

And here I am now reporting from an extended weekend in Brussels. It's kind of stupid that I have to leave Regensburg just at the moment when results in the lab get really interesting. But then, I'm staying online all the time anyway, and this weekend is FOSDEM time. Definitely a great opportunity to meet with some of the other Gentoo devs face to face. We had the Gentoo developers FOSDEM dinner yesterday, finishing with good Belgian beer near the Grand Place. So far it has been a lot of fun. We even have quorums for both the Gentoo Council and the Gentoo KDE team here...

At the conference site I sometimes have this weird feeling of visiting the nerd pole. One of the events definitly freaking out the locals was the outdoor GPG keysigning. Imagine cold windy weather and 150 geeks standing in a line along the curb and swapping passports for two hours... Just now I'm listening to an interesting and very funny talk about the LibreOffice fork. ("Are you German? We need your help deciphering the code comments! What does 'Manta-Hack' mean? And, 'Wenn Sie das lesen k├Ânnen, haben Sie eine Waschmaschine gewonnen!'???)

The weekend is way too short anyway. Somehow I was not that much excited about visiting Brussels for the third time. Frites and mussels, bah. Now that I'm here, though, I think I should definitely come again. I barely remember the place, there are so many things to (re)visit, art nouveau buildings to discover, flea markets to stroll across, and everything related to Gaufres and Chocolat just has to be good. Cheers!

Thursday, February 3, 2011

Gentoo and GPIB (IEEE 488.2) device control: sci-libs/linux-gpib

Most of you will probably never have heard of the GPIB (IEEE 488.2) bus before. It's a pretty ancient (1960!), but robust parallel bus for addressing lab measurement equipment, which now supports up to 8 Mbyte/s. A clear specialist application, but one that is common for example in university labs all across the world. A typical PCI adapter card costs somewhere around €1k, a typical 3m cable (heavily shielded) somewhere around €250, but then, in many cases the attached hardware is far more expensive.

Under Linux, there are basically two ways to adress GPIB hardware:

As much of the hardware is bought from National Instruments, one is the proprietary National Instruments VISA driver stack on top of NI's GPIB hardware driver. This works very reliable (once it's installed), supports e.g. LabView for Linux (eurgh), and NI is actively developing drivers for (some of its) hardware. So much for the good sides. Here are it's disadvantages:
  1. installation is basically doing its own package management, only very few (mostly outdated) linux distributions are really supported and trying others can be a serious pain, and the entire installation process is fundamentally incompatible with portage (I've been trying to beat it into an ebuild for a while and this is a sure way to madness); 
  2. since the Linux kernel USB interface is declared GPL-only, no GPIB-USB devices are supported since kernel 2.6.24.
For those trying to use the excellent NI GPIB-USB interfaces in their labs, even NI employees point to the second option: the open-source (GPL) linux-gpib package. While its development has stalled in terms of features, it supports the usual hardware fine and interfaces even with most recent kernels, and the author wants to maintain it further to that effect. For this package, we now have an ebuild in Gentoo: sci-libs/linux-gpib. It is still package-masked since the installation needs testing. While we do have the required hardware in our labs, I have not had a chance to set up an entire Gentoo system there for it. But- if you have been working with linux-gpib and maybe even with one of the inofficial ebuilds before, please give it a try and report your experiences on bug 165399.

As a final remark, probably the best possible support would be to combine the open-source linux-gpib hardware driver with the NI VISA intermediate layer. Unfortunately, this would mean linking a GPL library and proprietary code, so no-go. At least as long as nobody budges...