linux.conf.au 2012 – Day 3 (Wednesday)

This week I’m at linux.conf.au, the southern hemisphere’s premier open-source conference. This year it is being held in Ballarat, about an hour’s travel from Melbourne. I’ll be documenting the trip and conference as much as I can given the limits of my enthusiasm and awakeness.

Wednesday 18th January:

Paul Fenwick is awesome!
Paul Fenwick is awesome!

Quite a few more talks today; seven to be exact. The first was Paul Fenwick’s keynote address on “All Your Brains Suck”, which is about ways of hacking and exploiting the human brain. It’s fascinating stuff, even if I had seen the talk before (when he visited UTAS and gave the talk to TUCS). I now know that scary but logically safe places (like rollercoasters) are good places for dates. And that priming people with slow words (like ‘elderly’) make them walk slower. Utterly crazy stuff, just like the speaker of this talk. 😀

After morning tea, there were two talks on filesystems. The first, on btrfs, was given by Avi Miller, who was an excellent speaker. btrfs seems like an amazing piece of kit. I had always thought that you couldn’t do much with a Linux filesystem; but I was shown to be wrong. btrfs does file-level RAID, so you can how many backup copies of a file you want on the disks. It also does copy-on-write, so you have backups into the immediate past as well. The next talk was on XFS, given by Dave Chinner, and he showed how the performance of XFS has jumped up in recent years, as good as btrfs (sometimes better) and they both far outstrip ext4 now (no surprise, ext4’s underlying technology is about two decades old).

The first talk after lunch was on Ubuntu’s ARM ports, and how development is progressing for the various ARM platforms (of which there seem to be hundreds). The most interesting thing for me was the coming-of-age of ARM servers, which consume far less power than x86 servers (a good thing for the environment) while doing a similar workload. Because most services don’t require CPU-intensive workloads, we can save even more! The second talk after lunch was on adding millions of watchpoints to a Linux system. Most Linux systems currently only support 2 or 4 watchpoints, and this isn’t enough for good security analysis. So they added a driver to Linux that steps through instructions when an out-of-memory page is accessed (via virtual memory). Clever stuff, even if most of it went over my head.

After afternoon tea, I watched two talks on bootloaders. The first, on using Linux as a bootloader (given by Peter Chubb), was interesting, though was really only useful as a method in a small number of cases. Most systems are better off sticking to something like GRUB. Speaking of GRUB, the second talk (given by Josh Triplett) was about porting Python to GRUB, and the resulting project, BITS. This seems like a fascinating thing to do, mostly because it blurs the line between what an application is and what an operating system is. This is a line that Emacs has been tiptoeing on for some time now, and it is nice to see it has a friend.

The Debian Swirl
The Debian Swirl

For dinner today, I attended the unprofessional delegates networking session (UnPDNS) which is held at the same time as the event for the professionals. We had a barbecue, which gave me a great opportunity to hang out with some of the other cool people who didn’t buy expensive tickets. 🙂

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