Archive for the ‘tech’ Category

How not to get bored while installing an operating system

Traditionally, installing (or re-installing) an operating system was a dull job. You’d feed your machine with floppy disks (or a single floppy and a single CD if you were lucky) and wait for ages while an hourglass twizzled around. And the screen would be full of platitudes, in a retro-VGA-style, about how much better your life would be. And a chorus of Angels would sing to hail the new computing experience. (Or they would if there were any sound drivers which worked by default).

But now things are different. I give you Ubuntu 8.10.

I must admit, I’m a long-time Linux zealot, having started with Slackware 1.something with (I think) a 1.3.20 kernel. I did install it from floppy disks. I did cycle from home to University campus several times with bundles of floppies containing XFree86. I did rashly install Netscape Navigator and wondered if I’d miss NCSA Mosaic. *sigh*

Back to the present. I’m installing Ubuntu on this laptop. I’m also browsing the web and writing this blog post. On the same machine. It booted from a USB stick into a usable system and is installing in the background.

And here’s the inspiration for this post, an example of how polished the system is:
Migrating stuff from other OSes

Yep, I know. Hardly earth-shattering. But these are the missing bits of fluff that Gnu/Linux distros have been missing.

Anyway… while it’s installing, I’ve got some web-browsing to do. (Did I mention that I can do that? Wirelessly? Oh…)

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Filed under tech : Comments (0) : Nov 4th, 2008

Bye-bye Smile

After some protracted discussions with the folks at smile.co.uk, we seem to have hit stalemate. So I’m going elsewhere.

For anyone else who’s being cornered by Smile, do note that they will allow customers to opt-out of the scheme. But, for me, that’s not the point.

I’m minded to think that VBV, while far from perfect, is better than nothing. But you’ve got to get the implementation right!

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Filed under tech : Comments (0) : Oct 21st, 2008

Audio support in J2ME and J2SE

So I’d like to capture some audio using a Java program, and play it back using a different Java program. I don’t care what encoding I use. Easy, right?

No, unfortunately not. Because the recording is to be done using J2ME (and JSR-135) on a mobile phone… but played back with a J2SE application on my desktop PC.

And guess what? There isn’t a single common codec! My phone only supports AMR, but the Java Media Framework supports everything but.

FFS! :(

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Filed under tech : Comments (0) : Sep 14th, 2008

Not Smile-ing about Verified By Visa

“Verified By Visa“. Internet shopping saviour, or a dangerous tool which lulls users into a false sense of security?

On the face of it, VbV looks like a great idea. Before completing an online order, you need to enter a security phrase which only you and your bank know - so you can be sure that no-one can shop using your debit card without permission.

So what could possibly go wrong?

Where does the HTTP POST go to?

In the case of ‘dabs.com’, the VbV web form will be submitted to “secure5.arcot.com”. Who? Exactly. Not my bank, not the merchant, but a previously-unknown third party. And the location bar helpfully says “https://www.dabs.com/”. So that’s not much bloody use.

And the password will be sent to my bank for verification?

OK, let’s assume we trust “secure5.arcot.com”. How do we know that they’ll send the details to our bank for verification, and not to a bunch of Russian mobsters?

In the case of “dabs.com”, the bank’s logo is shown - so we can be confident, right?

Wrong! The first four or six digits of a visa card number comprise the “Issuer Identification Number” which are well known. So any Tom, Dick or Harry could stick the correct bank logo on a phishing webpage and ask for my VbV password.

And with Smile, it’s worse still

I guess they’re just trying to be helpful, but they failed miserably. The Verified By Visa password is set to be the same as one of my “Secure Personal Information” details… specifically, the “memorable name”. I have two problems with this:

  • First, many (most?) people would automatically use their mother’s maiden name, which is quite discoverable with a little social engineering
  • Second, this means that a piece of private login data - formerly used purely for online banking - is now going to be sent to other places, such as “arcot.com”.

On one hand, the bank encourages us to not write down passwords or share them with anyone, but now expect us to give the same password to a third party every time we do a transaction on the internet?

Finally, it appears that (with Smile bank, at least) I can neither opt out of VbV nor change the VbV passphrase independently of my online-banking login details.

I’m starting to wonder whether I want to stick with a bank with such a misguided approach to security.

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Filed under tech : Comments (0) : Sep 9th, 2008

Extreme Tips for Unmaintainable MIDlets

I stumbled on a blog post containing “Extreme Tips for Lightning-Fast MIDlets“. Let’s look at some of these programming gems:

Avoid synchronization when possible

Mmm, okay. Don’t know about you, but I synchronize code only when I need it. Perhaps the author of this article likes to synchronize on a whim? Not me…

Array-spreading

Example:

// Before
int[][] table; // a 4×4 table

// After
int[] table; // a 1×16 table

WTF?! Let’s look at the pros and cons of this:

Pros:

  • marginally quicker

Cons:

  • extra computation needed to find the correct array element, if the data structure is supposed to model multi-dimensional data. Espcially relevant if the number of the items in the first dimension isn’t fixed at compile-time
  • yields code which is more difficult to maintain. Associated risk of introducing bugs

Read the rest of this entry »

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Filed under tech : Comments (0) : Aug 5th, 2008

Voyager 2110 router / Plus.net / disconnects / firmware

(Not the most imaginitive post title, but…!)

I stupidly upgraded the firmware in my BT Voyager 2110 router to the latest version, 3.03c. Stupid, stupid, stupid. “If it ain’t broke…”, etc.

The 3.03c firmware has fails to automatically reconnect whenever the line drops, as it does regularly around these parts. So I had three options:

  1. Whinge, moan, drink whisky, kick the cat
  2. Write a script which automatically hits the [Connect] button in the web interface every minute
  3. Find some firmware which doesn’t have the problem

Given that I have no cat, and absolutely no desire to write a shitty script to fix a stupid problem, it ended in a firmware hunt.

Turns out that the nice folk at Andrews and Arnold have seen this problem before. And they’ve got the GPL’d sources from BT and fixed the problem too. Nice work chaps! (Now all you need to do is fix the crufty rebranding exercise in the admin web pages of the router - which looks like it was done by a 5 year-old)

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Filed under tech : Comments (0) : Jun 24th, 2008

Scheduled throttling of torrents

I switched to plus.net, partly because I fancied a change, but also because the previous ISP was charging 25 quid for a similar service. PlusNet, like most providers nowadays, have a usage allowance - but usage between midnight and 8am doesn’t count. So that sounds like an ideal time to run those Ubuntu ISO torrents at full throttle.

rtorrent can be configured to run internal commands on a schedule, so it’s pretty east to tweak rtorrent’s throttling automatically:

# initial rates
schedule = upload_throttle_default,0,0,upload_rate=1
schedule = download_throttle_default,0,0,download_rate=1
# free period starts at midnight
schedule = upload_throttle_free_start,00:01:00,24:00:00,upload_rate=25
schedule = download_throttle_free_start,00:01:00,24:00:00,download_rate=200
# free period ends at 8am
schedule = upload_throttle_free_end,07:59:00,24:00:00,upload_rate=1
schedule = download_throttle_free_end,07:59:00,24:00:00,download_rate=1

And since the Kurobox is a stratum 2 NTP server, I reckon it’ll throttle at just about the right time…

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Filed under tech : Comments (0) : Jun 20th, 2008

On “Welte vs. Skype Technologies”

So, Skype backed down.

Now, I don’t have anything against Skype, or closed source products in general. (Heck, I write closed source code for a living.) But you’ve got to play fair and either accept a license completely, or decline it completely.

The GPL takes the default Copyright scheme and makes it more free. Skype argued that the GPL was illegal, unconstitutional and responsible for the deaths of kittens. But whether that’s true or not is irrelevant. If it were ruled that the GPL was unconstitutional in Germany, then that would leave GPL’d code still subject to plain old Copyright. So you can’t just do what you like with it.

It’s like having an orchard of apple trees with a sign outside: “Free apples. Pick your own. No tractors.” Then someone drives a tractor around your orchard, claiming “who are you to stop me driving my tractor?”. Well, it’s my orchard. My apples. My rules.

So we wait with baited breath: will Skype quietly can the offending product, or release the code? I’m hoping for the code - otherwise some folks might accuse GPL of stifling innovation. And we don’t want GPL to be a big scary monster.

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Filed under tech : Comments (0) : May 15th, 2008

Memory for the Packard Bell EasyNote A8202

For the avoidance of doubt, the Packard Bell EasyNote A8202 uses DDR memory, not DDR2. Despite what many websites might say.

(Grr!)

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Filed under tech : Comments (0) : May 14th, 2008

Popcorn Hour arrives

So the Popcorn Hour arrived. (Yeah, terrible name, I know.) And it works a treat, too, connected indirectly to the wireless network using my Squeezebox Receiver as the wireless bridge.

I was concerned that the wireless thing wouldn’t have sufficient bandwidth to properly stream video - but I haven’t seen any problems so far.

The setup was dead easy, configuring the network and connecting to an NFS share on the Kurobox was a breeze.

I have one or two minor niggles with the firmware onboard the PCH, but it’s generally excellent. :D

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Filed under tech : Comments (0) : May 8th, 2008

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