A solution for Debian mirroring?

Sep 20, 2005 / 0 comments

Recently security.debian.org has been having some problems with maxing out its connection due to an X update. This reminded me of a conversation I had at DebConf5 about the feasibility of a Debian anycast instance. This was originally under the guise of ftp.debian.org, but there's no reason it wouldn't work nicely for security.debian.org as well.

The idea is that Debian would obtain a /24 of PI (or something unlikely to get filtered anyway; I think anything smaller wouldn't work) and their own AS. They'd then host instances of f.d.o/s.d.o around the world with ISPs that would route this AS for them. This would mean that big sponsors able to provide global routes would still be able to do so, but smaller sponsors (like Black Cat) would still be able to help out by announcing the route to their peers.

You'd need the servers involved to all be reliable push mirrors, so that they're as close to being in sync as possible. And I'm not sure how well TCP works over anycast; assuming stable routing I can't see why it'd be a problem (does the Akamai service work this way?). Certainly it seems to be quite common for major DNS servers these days. But it could end up with quite a few decent local mirrors with no work required on the part of the users to take advantage of them. Am I insane?

Mapping the world for free

Sep 18, 2005 / 0 comments

I had a conversation a few weeks ago with Tristam and some other people about direction finding in terms of car navigation systems, and how I felt it reduced to a weighted directed graph and that it should be possible to build from a large enough set of GPS logs. There was general agreement that this wasn't unreasonable. This prompted me to actually see what was out there, which led me to OpenStreetMap, who have been going for over a year now and see to have a reasonable number of people involved.

They lack any data around Norwich however, so I thought I'd see what I could do to remedy that. I bought a basic USB GPS device, hooked it up to my laptop, installed gpsd and gpsdrive and went for a test drive. gpsdrive seemed to be doing the right thing, with the track it drew matching up with the map being displayed. However when I uploaded it to OSM it seems to be out by a reasonably constant factor. This has led me into the tricky world of GPS datums and hoping that that's what at fault rather than it being the fact I bought a cheap Haicom Hi-202 rather than something more expensive. quinophex has a Garmin however, so he's going to lend it to me so I can run the 2 side by side and see what happens. It'd be really nice if I discovered it's just a conversion thing and that the tracks I got of a trip to and from Redbus could still be imported...

Anyway, if you do GPS stuff at all I'd highly recommend uploading some tracks of your local area and even potentially doing some markup of nodes and streets; if everybody just did a little bit local to them and perhaps a few longer journeys then things should start to get linked up and filled out, which would increase the appeal a lot.

Useful v600i BlueTooth tips.

Sep 7, 2005 / 0 comments

I suspect these apply to lots of Sony Ericsson phones, but I know they definitely work with my v600i and I couldn't find them anywhere all together.

  • Asking the phone for a non existent file via obexftp makes it very unhappy; apparently often to the point where the phone needs turned off and on again. This is bad.
  • ussp-push is your friend.
  • To send a vCard (or many in one file) to the phone, do: ussp-push <BT ADDRESS>@5 <local vcard file> pb.vcf. The phone will recognise the "pb.vcf" (in particular the .vcf extension I believe) and ask if you want to import the contacts.
  • To send a Java App (ie a .jar file) do: ussp-push <BT ADDRESS>@5 <app.jar> <app.jar>. Again the phone will recognise the extension and then ask where you want to save it - under Games or Applications.
  • The normal AT dialup/GPRS command set works fine on rfcomm channel 1.

Things that need to be invented

Sep 6, 2005 / 0 comments

I'm a keen believer that we need some more interesting applications for pie-in-the-sky technology. My favourite example is the time machine fridge. What better use for the idea of time travel? Every time you need an ingredient from the fridge, not only do you have it - it's fresh! I was explaining this idea at TFM's BBQ on Saturday and Ian Snell came up with a potentially better idea; the stasis fridge. Want things to stay as fresh as the moment you put them into the fridge? No problem. What to keep your hot pizza beside your cold beer? Done.

My other neat idea is the wormhole router; get round that pesky speed of light limitation of packets crossing the Atlantic by having paired routers with a wormhole between them. Loadsa bandwidth, tiny latency. No danger of a trawler cutting your fibre!

The problem, of course, is that no one's actually got round to inventing time travel, stasis or wormholes yet. Bah.

Gadgets Galore #2: Toshiba Portégé R200

Sep 5, 2005 / 0 comments

My second gadget in the past week was a new laptop. I've discussed this before and ended up with the R200. Built in bluetooth + wireless and 512MB RAM; more than my old N200. I'd seen Chris Walker's R100 at Steve's annual August BBQ and he said he was happy with build quality, so that convinced me. It's very nice; light, looks good, even came with a little cloth to put between the screen and keyboard when it's shut (numerous people have told me they put a piece of paper in or similar for their laptops to avoid finger muck getting on the screen, so I thought it was a nice touch by Toshiba).

Installation was fun (in a sick, I like fiddling sort of way). No removable drives. And the in built ethernet isn't supported by a stock kernel. Hmmm. So I ended up booting from an SD card that happens to have GRUB on it in my SD/USB convertor, and then reading the mini install ISO off my iAudio, and then doing the rest of the install over the network using a PCMCIA 8139too based card I had lying around. If I'd had a big enough SD card or USB memory stick the easy solution would have just to do a full install off that, but I don't.

The whole thing is patchtastic. The internal GigE ethernet isn't supported by 2.6.13, but you can download a patch from Marvell. The internal wireless is Atheros, which needs the non-free madwifi driver (though I must try the Free ath-driver at some point). Bluetooth appears as a normal USB device, supported by hci_usb. However it doesn't appear on the bus without an ACPI patch to allow toshset to enable it (I possibly could have enabled /dev/toshiba support as well). The video is an i915 chipset, which isn't supported by the XFree86 in Etch, so I'm waiting for xorg to propagate from Sid before installing X. Good job I'm a text mode junkie, eh?

That sounds like a bad review, but I'm really happy with it. Everthing is actually supported (well, except the SD slot and the fingerprint reader), just not in the default kernel. It's light, it looks cool, I'm easily getting 3+ hrs battery life out of it and that's before I've looked at doing stuff like laptop-mode or auto cpufreq.

Oh, and although I'm running Debian on it, the Ubuntu R200 wiki page was really useful as a starting point.

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