Archive for May, 2009

52/30/5 Week 16

May 17th, 2009

Week 16 is a few weeks late, and the backlog is going to get bigger before it gets smaller. I’m off to Europe in a weeks time, so expect to see quite a lot of photos from that to make up the backlog, and maybe even help me build up a bit of a buffer.

This week takes me up the hill near my house, Fadden Hills, along with a shiny new D90 camera and a couple of new lenses to play with.

A survey mark on the road up to the hill:

Survey Mark

A fence at the start of the hill.


Helen walking up the hill with the mountains in the background:

Walking uphill

Woden valley looking towards Telstra tower:

Woden Valley

A couple of the kangaroos around the hill:


That’s it for this week. I’ll try and get another week done next Sunday, and after that there will be a break while I’m away from the Internet. You can find the full set online as always.

Wolfram Alpha – the good, the bad, the ugly

May 17th, 2009

The most interesting search engine to be launched in years just went public: Wolfram Alpha

Wolfram Alpha sells itself as a ‘computational knowledge engine’. And it’s a very nice proof of concept. But as it stands there’s some things about it that are quite poorly developed, and some things that should be removed immediately.

Search of US GDP to get an idea of what it can do. You get a nice output of the value per year, automatically converted into $A in my case.

But some of the data here is badly out of date. For instance:


GDP per capita 16th in the world? There are a few countries ahead of the US, but it shouldn’t be that many. Wikipedia (which looks right, but I haven’t double checked) says that the US should be more like 4th to 6th. It looks like it’s a combination of counting things as countries that economists don’t normally include, but also a product of outdated data.

Let’s try another example – seach for my name. A bit US centric, but that’s only to be expected I suppose. But here’s the neatest bit: if someone’s name is Robert, how old are they likely to be:


The system has pretty sharp limits. For instance, at the moment I’m interested in Australia’s GDP growth. The basic search works fine, but the most recent growth rate they have is 2005. Which makes that search completely useless – what’s important is now, not 4 years ago. And even the US only has growth rates from 2005. That’s bad, bordering on dangerous for people who don’t check the fine print.

But finally, moving on to the ugly. If you search for a stock you get a lot of data. Try Google as a search on Wolfram Alpha. Mostly a nice summary of market data on the company, fine. But down towards the bottom of the page you get this:


There is no way to describe this but dangerous and irresponsible. This projection will change every time you open the page, so don’t expect to see the results each time. The engine takes a well understood random walk approach, and produces projections using no information other than the historical variations in the stock.

But that’s a very silly thing to do. Sure, over history stocks and other real values seem to follow something that looks like a random walk. But that doesn’t mean that any individual random walk is of value. Or even a set of 5. This forecast has as much value as me asking my cat to walk across a sheet of paper with muddy paws, and then using the positions of the marks to project the stock. Soothsayers looking at entrails have more credibility than this, because they’re at least using their own judgement and intuition subconsciously.

Any informed observer won’t get hurt by this, but what about someone who isn’t that literate in this sort of analysis? What if the random odds give five paths that all point well up? And what if they then go and put their life savings in the stock as well.

If this sort of analysis is going to be included on the Wolfram Alpha search engine then it needs to be accompanied by far more prominent warnings about the use of this sort of analysis, as opposed to their current totally inadequate disclaimer.

How to build a small media centre PC for standard definition TV for less than $A 500

May 5th, 2009

I decided that I needed a new TV to put in my bedroom. Also, it’s been a year since I played with building a computer, so I decided to try my hand at building an Intel Atom based PC.


A quick glance over AusPCMarket, and a quick email to Dan of Dansdata led me to get the following parts (all prices in Australian dollars):


After that I just needed one more parts, which I got from JB Hi-Fi:

  • ASUS 13″ Widescreen monitor, $98.00

Total cost was $445.02.


Step 1: Open the case up.


The Aywun case is quite small, and just needs two thumb screws removed to take it out. There’s a frame to attach the slimline CD drive and a hard drive, but I won’t be needing those for this configuration.

Step 2: Insert the port template into the case.



Step 3: Attach the motherboard to the case.


It’s a small case, this was a bit of a tight fit and needed a little bit of juggling around to fit everything in.

Step 4: Insert the memory into the motherboard.



As always with memory, I put it in the wrong way around the first time I tried. Fortunately it’s pretty hard to get DDR2 RAM wrong. Just push gently and the RAM locks in place.

Step 5: Attach the front panel cables to the motherboard.


These fiddly cables were a lot easier than the last PC I built – this is normally the bit I end up cursing, but this time it only took a minute.

Step 6: Attach the power cable to the motherboard.


Step 7: Close the case up.



I’m leaving the drive frame out, so keeping the cables neat is pretty easy. With a CD drive and a hard drive power and heat management would start to be a problem.

Step 8: Attach monitor.

Step 9: Boot and check configuration.


As it turns out, the BIOS for this motherboard is well set up to use with a USB stick rather than a hard drive – it was probably easier to set up than if I needed to boot from HDD…


To run this computer I chose XBox Media Centre, mainly because I’ve used it before and been happy with it, but also because it comes with a live CD.

Step 1: XBMC Live image.

The version of XBMC to use is the live version, which includes a cutdown version of Ubuntu.

Step 2: Install to USB stick.

The slightly tricky bit is that, by default, you can’t simply copy the XBMC live onto a USB stick, as it needs a Linux file system. So to run the thing most easily, I downloaded VirtualBox.

I then just set up a simple virtual machine with no devices attached other than the USB stick and the ISO image in the CD drive.

After that, these instructions got me the rest of the way. The only tricky bit was it didn’t recognise the USB stick initially, so I had to remove it from the computer and put it back in again, after which it worked fine.

Step 3: Boot computer from USB.

To make sure that there weren’t any problems with the software, first I booted my main PC from the USB. Once that was confirmed to work, I moved on to the new box.


Everything worked first time with little problems.

Next Steps

So now I have a small PC that boots and runs XBMC.

Still a couple of things to get working before it’s ready to go:

  • The remote control needs to be configured. At the moment the buttons aren’t working properly. It turns out that rather than showing up as an IR receiver, it’s showing up as a keyboard. I just need to find some way to map the keys properly.

  • A slightly bigger issue is networking. The USB wireless stick I have isn’t working out of the box at the moment, so either I need to get it working, or go to the backup plan (using an old router I have set up in bridge mode).

  • I haven’t tested the sound yet – it’d be surprising if it was a problem, though.