From the Canyon Edge -- :-Dustin

Thursday, January 21, 2010

LCA2010: Day 5, Wellington, New Zealand

The day opened with a series of Lightning Talks. Unfortunately, I missed most of these as I had some issues with checkout at the hotel. Paul Fenwick's was a hilarious satire about unfriending people on Facebook.

Next, I attended Andrew Tridgell talk on Patent Defense for FOSS Developers. Having worked at IBM previously, I (unfortunately) have read many, many patents. Tridge's talk was about how to read a patent. The most interesting point he made was about triple damages. Many open source projects (or companies) have a "don't read patents so that we're not one day liable for triple damages" policy. Tridge says this is dumb for open source projects/companies. If they're sued for damages for infringing a patent, then they're probably dead bankrupt. If they're sued for triple damages, well, they're still probably dead bankrupt ;-)

He talked about the three types of patent defense:
  • non-infringement - we don't do that - best defense
  • prior-art - someone did that before - very tricky
  • invalidity - you can't claim that - almost impossible
The most important part is independent versus dependent claims. When working against a patent, focus on the independent claims. Prove that you don't offend those, and you won't offend the dependent claims either. And when looking at the independent claims, focus on the elements. Try to find elements that you omit.

I've read more patents that I care to admit, and I pray that I can avoid being dragged back into that world again. That said, God bless the people who still are doing this today. They're doing this behind the scenes, and they're getting no credit whatsoever for it. Thank you so much. What you're doing for us is more valuable than anyone knows.

Next, I attended Arnd Bergmann's talk on Virtual Network Switching across Hypervisors. Current virtual networking in KVM looks like a basic switch/router (showing a basic home Linksys router on a slide). If that's all you want, that works pretty much fine. Arnd is working on all the other complex networks, bridging, VLANs, etc. I'm following his work quite closely on the upstream mailing lists. His slides are available at:

I spent the next several hours with David Howells from Red Hat (author of keyutils and the linux kernel keyring). He was helping me with a small, but invasive change to the way eCryptfs Encrypted Home Directories loads keys into the keyring. He helped me move the keys from the user keyring to the session keyring. This will improve the clearing and expiration of keys once I've tested and released it. Many, many thanks to David for his help and patience. Cheers!

Rusty Russell gave his usual excellent presentation, this time about Hacking a Wiiremote for his 2 year old daughter. Funny, cute presentation. Basically, he attached a series of LEDs to a scrunchy that his daughter would wear on her wrist. The Wiiremote detects movent of the LEDs, and it's attached to a Linux system where his code runs, using libcwiid (pronounced lib-seaweed, heh). He wrote a couple of Python programs, one that lets her smear paint on the TV screen, and another that lets her smack a baseball bouncing around the screen. Rusty is the quintessential hacker ;-)

And, alas, the week is over... Finally, the Closing Session. Lots of thank you's all around. These guys and gals put on an amazing conference. I hope I'm so lucky as to attend again some time.

From here, I'm taking a couple of days off, and hiking the Routeburn Track, one of New Zealands 5 Great Walks. I'm really looking forward to a couple of days unplugged, and in the Kiwi back country. Hopefully I'll get some beautiful pictures, and have some stories to tell in another post.

Kia ora,