11:11am: Redundancy
I have now officially been served notice of redundancy and I'm on gardening leave. I've got a new job lined up in Glasgow, so it's all for the best. Thank you for your attention.

2:11am: Gravity, sci-fi and wormholes
I've read more than one piece of sci-fi where some sort of wormhole transport technology can only function far away from the gravitational fields of planets, but is revealed also to function anywhere the gravitational potential field has a zero gradient: at Lagrange points or even at the centres of planetary bodies. I wonder, though, is this plausible? I assumed at first that the requirement to be far away from planets was so as to be on a relatively "flat" area of space where there's negligible variation in the gravitational force acting on different parts of a large structure. However, I do not think this would work for Lagrange points. It seems to me they would be just as bad as (or maybe worse than) the supposedly bad areas in orbit. But (given our current understanding of physics) could a physical phenomenon be sensitive to the gravitational potential gradient? After all, there's nothing fundamentally distinguishable about being static in no gravitational field and free-falling in a constant field, is there?

And yes, I know we need some sort of new physics to create and dispose of these convenient wormholes in the first place. You can just say it's fiction and that's the way it works. But it's clearly supposed to be pretty similar to the physics we understand, and I wonder what those more versed in physics think of all this.

7:01pm: Scribblenauts
I spent a while playing Scribblenauts recently. For those not familiar with it, it's a game for the Nintendo DS where you solve puzzles by writing out the names of objects you'd like and then using them to achieve some goal, such as guiding home a lost cow, jump-starting a car or saving a princess from a witch. I'm still not sure what I think of it. To begin with it's amazing. You imagine something that would be useful, write it in and it appears! The game knows a surprising number of words. My problem is that after a while I find that although there are a huge number of different items, I can't find all that many different strategies for the situations it keeps putting you in.

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11:55pm: Choosy about fonts
Font rendering is mostly pretty good for me on Ubuntu. But I do have a problem with some fonts on some web-pages:



Liberation Sans gets substituted in when websites request Arial. What is wrong with those "y"s? They're hideous! They look like they came from a completely different font. Is it just bad hinting? I tried messing about with the system font hinting settings, but they don't seem to affect how Firefox renders fonts on the web.



Bitstream Vera Sans seems to be the standard sans-serif font through Ubuntu. It's quite nice at large sizes, but after reading it over and over again at small sizes, those capital "W"s are slowly driving me crazy. They look ugly and splayed out. I guess it's a hinting thing again?

Does this sort of thing bother anybody else? Are there better fonts I should be using on Linux? Or something I can do to make it render the same fonts more nicely?

1:37am: I have difficulty with popular culture

I have difficulty with popular culture

...particularly when it comes to music.



At least when they wear funny costumes I have half a chance of remembering them.

1:45pm: IOI 2009 - Day 0 - Museum
Next we have the "Museum" question.
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11:46am: IOI 2009 - Day 0 - Hill
Okay, first up, the "hill" question.
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11:33am: International Olympiad in Informatics 2009
This year's informatics olympiad is this week. There are (I think) four questions each day on Monday, Tuesday and Wednesday. While the contestants take part in Bulgaria, you can follow along at home and submit your answers on the web. Generally you have a problem to solve and must write a program (in C, C++ or Pascal) to solve it within certain time and memory constraints. You can then upload your program to their server and it will be run on secret test data. When the contest is over your grade will be determined by how many test cases it passed. Generally an inefficient program can still gain some marks, but you'll need something with good computational complexity to get maximum marks.

There are training questions already up to get you familiar with the system. The first is deliberately trivial, but the remaining two are rather interesting. Go have a look. I'm going to follow up with a post on each of them to discuss my attempts at solutions.

EDIT - Here's my post on Hill, and my post on Museum.

7:03pm: Needing some Linux advice
It looks like my laptop is in bad shape again. Last time it was upgrading to Ubuntu Jaunty - some video driver or something disagreed with it, resulting in random hanging, and it seems the hanging resulted in file-system corruption, which could be repaired by fsck, but still left me with critical parts of the system not working and no clue how to restore them without reinstalling. I reinstalled Jaunty once and the same thing happened. Then I gave up on Jaunty.

So for the past few months I've been running Ubuntu Intrepid. It worked more or less okay. But the other day I made the mistake of plugging in my mobile phone to try to upload media onto it. Apparently there's a known bug that causes a kernel "oops" when you plug in a USB device which has malformed responses to some message or other. This resulted in a system that hung on shutdown. And now it seems that forcing it to power down has corrupted the file-system. Some time after rebooting, everything stopped working and I discovered a message in the system log that the file-system's journal was aborted and it was remounted read-only. Upon rebooting it tells me that it needs to run fsck to repair stuff. I've still to do that, but I expect that even if it succeeds I'll be back in a situation where important files are missing or corrupt and I'll have to reinstall.

So, kind reader - what should I do? I have a vaguely recent backup of my home folder, and I suspect I can probably salvage most of what's there on the drive right now. But I'm not loving the Ubuntu experience. It seems dreadfully unstable... but are other distros any better? I'm running the 64-bit version, should I consider a 32-bit one?

These are the things I would like from my Linux:

• Rarely or never suffers total system death as a result of crashes or loss of power.
  
• Provides a straightforward way to roll-back upgrades that introduce instability.
  
• Runs X-windows.
  
• Runs a web browser and Flash applets.
  
• Has working sound on my laptop. (It works on Ubuntu, but is much quieter than on Vista, and despite much research I never managed to fix that.)
  
• Runs Pidgin or something else that lets me log into Google Talk.
  
• Lets me run Python 2.6 and Pygame (which uses SDL for rendering/sound/input).
  
• Doesn't force me to grovel through config files for basic configuration.
  
• Has a package manager that will fetch upgrades for me automatically.
  
• I was using xmonad as a window manager but still using Gnome for the panels like the system tray icons and the basic menus. I'd like to still do something like that, but I don't really care if it's Gnome or something else doing the system tray icons and whatnot.
  
• I would really like something that provides something like system restore points in Windows. Even if my home directory is nicely backed up I don't like having to go through a lot of rigmarole to reinstall the OS and then figure out what packages I had before.

Does this suggest any particular distro that would be good for me? Also, I think I've suffered from a laptop that's not particularly Linux-friendly. I have Vista installed in it too, but I haven't booted it for months. The next time I'm buying a laptop, how should I go about getting one that will result in a good Linux experience?

9:53am: BBC Advert followup
For those who are interested, I got a reply from the BBC:

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