Richard Jones' Log

Sat, 24 Mar 2007
Python Game Programming Challenge #4 -- theme voting has started!

The next PyWeek game programming challenge starts next Sunday at 00:00UTC. If you're interested, there's definitely still time to sign up to the challenge.

Theme voting has started. You may now log into (or sign up to ;) the PyWeek website to lodge your vote for theme. The themes to choose from are:

  • The only way is up
  • Underneath the radar
  • One way or another
  • Don't stop till you get enough
  • The final countdown
Argh, more RAID problems :(

So now my RAID has decided to do something completely new: not work whenever I reboot.

When I boot up there's a message in my console saying that the superblock on /dev/sda4 (one of the two disks) doesn't match and that it's giving up.

This means that every time I boot up I have to edit the mdadm.conf file to remove /dev/sda4, run "mdadm -A /dev/md0" to have it create the array again, re-add /dev/sda4 to the config file and run "mdadm --manage /dev/md0 --add /dev/sda4". Then wait as it rebuilds the array (usually takes about 15 minutes). Then I can again mount /home and use my computer.

I have been unable to find anything about this on the 'net either, which makes me sad. I wish I knew why /dev/sda4 was getting out of sync...

category: News | permanent link
Fri, 23 Mar 2007
PS3 distributed compute farm?

So apparently PS3s are kicking butt in distributed protein-folding. According to the folding@home FAQ, "With about 40,000 such machines, we would be able to achieve performance on the petaflop scale."

Makes me wonder how feasible would it be for PS3 owners to lease their hardware to a distributed processing company...

Just so we're clear on this, the fastest supercomputer on the planet* as of November 2006 was the IBM BlueGene/L system with 280.6 teraflops. Now, the benchmark is different of course, but the PS3 contribution to folding@home is (as of today) 497 tflops (that's with 20,287 participants). Not bad for a video game console.

I can't find rankings of distributed computing systems... does anyone know whether such a thing exists?

*: OK, except the one the NSA uses to decode the brainwave patterns scanned from the heads of every single person on the planet using their secret laser satellites.

Wed, 21 Mar 2007
Not designed for me

They made the floor out of glass too!

(To those not in the know, I've developed a slight case of vertigo that I first noticed a few years back whilst travelling overseas -- standing over that little glass window at the top of the dome in St Paul's in London.)

category: News | permanent link
Linux fun with grub and mdadm

Last weekend I decided to upgrade to Ubuntu's latest pre-release, Feisty Fawn (release 5) via Kubunutu.

Everything went swimmingly except there were two hitches, both disk-related. My motherboard has a dodgy SATA socket resulting in the BIOS not correctly detecting a drive plugged into that socket about once in every three boots*. There's no subsequent problems with the drive - it's just on boot-up. The result of this is that the BIOS ordering of drives (boot ordering) is slightly different to how Linux sees the drives. This in turn confuses grub which can't seem to figure out what disk to boot from when it configures itself. In the process of solving this issue I discovered the "device.map" file which solved my problem for a little while. Much rebooting and fiddling with grub ensues. I give thanks to the bright person who decided to make the Kubuntu (and presumably Ubuntu "proper") install disk a Live CD giving me access to both a terminal and a web browser with 'net access. Very, very cool.

* this has been a minor annoyance in the time I've had the computer but it's not annoyed me enough - until now with the grub experience - to try to solve it. Until now it just meant that I had to manually hit the boot menu in the BIOS to boot up. A minor inconvenience. The solution was pretty simple - just shuffling the three disks so they avoided SATA port 1 and used ports 2, 3 and 4. This solved my grub problem and as a secondary result I can now boot my computer without manual intervention ;)

It does bring me to my second problem: shifting the drives confused my RAID setup so I had to invoke the mystical mdadm to fix that up. Someone really needs to work on mdadm's interface... My biggest problems stemmed from two things:

  1. Trying to figure out the correct invocation to make it add both disks to my RAID array.
  2. Realising that if I got the command-line invocations incorrect I would receive no error, just nothing would happen.

Yes, if I invoked "mdadm /dev/md0 --detail" I would receive some output, but if I instead said "mdadm --detail /dev/md0" I would receive the detailed output that I was actually after. Also, if I "mdadm --manage /dev/md0 -a /dev/sdc4" to add my disk, nothing would happen. No error. Certainly no disk being added to the array. Changing the "-a" to "--add" made it do the right thing. There were numerous other times that I was scratching my head, chasing up false leads tryig to make the damn thing work all because I'd misread a usage statement, given mdadm the slightly wrong argument and it'd just ignored the argument rather than raising an error.

Tue, 20 Mar 2007
Women in IT article in The Age

Rachel's already mentioned this but I though it would be worth reprinting her words here to reach a broader audience:

Sarah Stokely has an article in today's Age about the formation of the Australian chapter of Linuxchix (who have a very cool logo). Reference is made to the unfortunate "softporn incident" of last year's Open Source Developers' Conference, so, as chair, Richard is quoted. To get the context of the apparently nonsensical quote you'll have to go to the original source.

I'll add that I attended an excellent talk on the same subject at the recent PyCon in Dallas presented by Anna Ravenscroft. That talk was eye-opening because although Anna had done quite a lot of research into the topic, the conclusion was that there was no single reason you point at to say "that's why there's less women in IT". Culture seemed to play the biggest role in various forms. My memory is fading, but I recall her mentioning problems with society at large, the culture of classrooms, of IT workplaces, of IT user groups and of IT as a "priesthood.

Anna and someone else at the talk mentioned a specific book that I've lost the name of in the time between the conference and getting home. I'd really like to try to find it ... this is a long shot but does anyone recall the title?

Fri, 09 Mar 2007
PyWeek #4 is open for registration!

PyWeek #4 (wow, 4 already!) is coming up in the first week of April. Specifically, 00:00 UTC 2007-04-01 to 00:00 UTC 2007-04-08. Visit the PyWeek website to sign up or read the rules. The PyWeek challenge:

  • Invites entrants to write a game in one week from scratch in Python either as an individual or in a team,
  • Is intended to be challenging and fun,
  • Will hopefully increase the public body of python game tools, code and expertise,
  • Will let a lot of people actually finish a game, and
  • May inspire new projects (see some games from previous challenges)
Mon, 05 Mar 2007
US tour continues

I had a wonderful weekend staying with my cousin Nat in Columbus, Ohio. We've not spent that much time together for ages and it was really great to catch up.

I'm at Mary and Bill's house at the moment (Bill's my boss at Common Ground) in Champaign, Illinois. We've spent pretty much the entire time here throwing around ideas about the OLPC, education, CGPublisher, continuous assessment, teaching programming, ...

More later - today is going to be a wild ride of meetings ...

category: News | permanent link
Thu, 01 Mar 2007
PyCon 2007 sprinting

It's the fourth and final day of sprinting here at PyCon. There's a general consensus that four days is too many - the strongest evidence being that there's very few of us actually left.

The "Game Sprint" has been about as disorganised as I'd expected. A few of us messed around writing games along the theme of "small" (with extremely loose interpretation ;). Mostly people used the exercise to learn pygame or PyOpenGL (or even in one case Python as well!) and write a game at the same time. Everyone seemed to have fun doing so, and there's now a few more people comfortable with the toolkits, which was the ultimate goal. A highlight was the Python newbie asking "who wrote pygame?" to which the response was pointing across the room to Pete Shinners "he's over there", and then "the guy who wrote PyOpenGL is over there, and the guy who wrote Python is over there" (Mike and Guido sprinting in the same room).

I spent some time tutoring, writing a little game for Abbey, rewriting the sprite engine in pyglet, talking through design issues with Pete and Phil Hassey and also chatting about the OLPC project with those sprinters.

The evenings tended to consist of game playing (galcon or board games) during and after which there was more discussion of various things. So many brains to pick and ideas to bounce around. I have a feeling I'll be revisiting that function inlining code...

category: Python | permanent link