July 31, 2008

iwconfig not setting essid?

If iwconfig wlan0 essid blah is seemingly not working when connecting to a open wireless network, then try




  1. iwconfig wlan0 essid blah

  2. iwconfig wlan0 key open

  3. iwconfig wlan0 enc off



The above seems to work for me by turning off encryption. It would appear with encryption enabled, iwconfig won't work for a open network because of some magic or other. If it still doesn't work, then try stick the above in your /etc/network/interfaces and prefix the commands with "wireless-", like so:



allow-hotplug wlan0

iface wlan0 inet dhcp

wireless-essid blah

wireless-key open

wireless-enc off



Hope this help some people, it drove me nuts!


Cheers,

Steve

July 24, 2008

grub, xfs, debian

Running grub-install with a XFS partition will likely fail - there is a reason lilo is used when XFS is root! The issue is grub-install creates the stage files in /boot/grub, which grub then expects to find when it accesses the disk directly using its own file system drivers. For most file systems sync is sufficient to force this to be true, but not with XFS - unless grubs's XFS drivers replays the journal, grub won't find the files. The detailed why of this is covered in this thread. To get around this, one needs to effectively replace sync with mount -r -o remount /; mount -w -o remount /. A quick a nasty way to get grub going with XFS partition is as follows:




  • init 1 # need single user mode to be able to remount root

  • cp /usr/sbin/grub-install /tmp # make a copy of grub-install to butcher

  • vim /tmp/grub-install

  • # now butcher grub-install as follows:

  • # 1. find the line that says "Sync to prevent GRUB from not finding stage files

  • # 2. deleted everything after sync

  • # 3. add exit 0 after sync for good measures

  • /tmp/grub-install # invoke our amputated grub-install to just produce the stage files

  • mount -r -o remount / # flush everything by mount as read only

  • mount -w -o remount / # remount since grub needs it to be rw

  • grub # invoke the grub shell

  • root (hdx,y) # manually specify the disk x partition y where /boot/grub/* is located

  • setup (hdx) # install grub into the disk x's MBR. DO NOT specify a partition number, XFS's sector 0 is NOT reserved for boot loaders!!

  • quit # exit grub

  • reboot # should work now




Cheers,

Steve

July 20, 2008

R18+, do want

Perhaps I am naive, but I expect those people in Government to have some resemblance of intelligence and be able to apply this very useful thing called logic. Michael Atkinson obviously isn't one such person. His recent reply to the demand for R18+ classification for Electronic Games [1] demonstrates a lack of intellect and foresight.



Firstly, Michael Atkinson can not see how have R18+ classification would a) stop parents from making bad choices and b) stop children getting hold of a game for their friend of sibling. Lets address these one at a time. Point a): MA15+ doesn't send a strong enough message to parents. If you are allowing children to purchase these games in the company of a parent or adult guardian, you are not sending a clear strong message that such games are not for children, at all. R18+ classification is a very strong message: these are prohibited to children, and it is illegal to make it available to them. Even the minimally functional or responsible parent will not purchase pornography for their children, and even the most apathetic cashier will not sell R18+ material to a minor. R18+ classification, if it existed, would an unmistakable message: DO NOT SELL OR EXPOSE TO MINORS.



Point b) can’t be any simpler. No cashier who wants to get paid, and no business which wants to stay in business, will sell to a child. If a child can not get hold of a R18+ game, it makes it impossible for said minor to get hold of it for their friends of siblings.



Secondly, Michael Atkinson believes introducing R18+ classification will increase the amount of inappropriate material for sale, and this will mean increased exposure of children to such material, since more of such material is for sale. What Michael Atkinson fails to realise is that introducing R18+ classification increases the volume of inappropriate material only very very slightly, while allowing the current volume of slightly less inappropriate material, namely games with MA15+ classification, to be reclassified as R18+ and thus have their exposure to children significantly reduced. Further, MA15+ restrictions only apply at the point of sale - it places no restrictions on whether the game must be played in the presence of an adult. R18+ classification will make it illegal to for a child to buy and play games considered inappropriate. In not having a R18+ classification for games, the Australian public is being done a disservice whereby the most restrictive classification is trivially circumvented.



Michael Atkinson then touts statistics like 79% of Australian house holds have a gaming device, and 62% of these Australians say classification of games has no influence on their buying decision. Seemingly solid statistics against introducing R18+ classification, except it is never mentioned which of these households have children under 15 - a household where all members are over 15 would care little for the classification of games they purchase. Further, given the current classification scheme’s weak delineation of games, it is not surprising that people ignore them.



The “violent games make violent children” card is of coursed played too. This is of course true - to say children is not affected by violent media would be a blatantly lie. However, the effect of violent video games compared to violence in television and magazines is not provably more or less. Michael Atkinson’s concerns are valid, but they are no more or less than concerns of any parent when it comes to violence in the media. If it is the basis on which Michael Atkinson voting against installing a R18+ classification, then I trust he is equally hard at work at removing R18+ classification for all other media as well.



Michael Atkinson then gives several examples of games that would supposedly be available under R18+ classification featuring strong themes of drug use and abuse. Ignoring the fact that thus far he has been arguing video games are bad because they lead to violence, there are two problems with this assertion. One is how Michael Atkinson knows these games will be classified under R18+ classification, when no such classification yet exists; and two, why we can’t demand the games be modified to fit R18+ or alternatively refuse classification of such games. Michael Atkinson suffers from the common fallacy that R18+ classification equates “anything goes” This is demonstrably false, as films have X18+ classification, and some films are still refused classification. Having R18+ classification does not rob us of the power to refuse classification for inappropriate games - in fact it only gives us more power to restrict exposure of such games to a greater degree than current classification scheme allows. This is especially true when Michael Atkinson says “What the present law does is to keep the most extreme material off the shelves” - R18+ classification will still allow the law to keep the most extreme material off the shelves.



There are several more flawed arguments in Michael Atkinson’s letter. One is the argument that if games can be made into MA15+, then obviously there is no need for R18+ classification. This is akin to saying that just because any film, television show, or magazine can be modified to be rated G, there is no need for anything over G. Another is the argument that film classification is different to video game classification because the age of moviegoers can be regulated. This is a blatant lie. The age of moviegoers is as well regulated as the age of video game purchasers, and just as ineffective. The only time when age of moviegoers is “well regulated” is when the film carries a R18+ classification. Michael Atkinson further differentiates film and games because “Access to electronic games, once in the home, cannot be policed and therefore games are easily accessible to children”. At this point I don’t know whether or not he is being serious - film classification extends to films on DVDs and on TV, where access in the home also cannot be policed.



Michael Atkinson expresses dissatisfaction with the current scheme - “I do not consider that allowing a child to play an MA15+ game is reasonable given the content set out in the National Classification Code...in South Australia effectively that does not prevent such a classification being purchased for the child or with the parent’s (or guardian’s) permission. It also does not stop a child from borrowing a game from another person or family member” What is stunning about this admission is that this is a problem which is helped by introducing a R18+ classification and reclassifying the more extreme MA15+ games as R18+ games. It would prevent such games from being purchased for a child, and it would make it illegal to lend or expose such a game to a child, say by allowing them to watch while you play. Even more amazingly, Michael Atkinson says he will “consider the merit in preventing MA15+ games to under 15 year olds, even with guardian or parental permission or assistance”. If he added another 3 years, he would effectively be considering R18+ classification to games.



Michael Atkinson in short presents no coherent or solid argument against R18+ classification for games. Despite his claim his decision was not conservatism for the sake of conservatism, it is precisely that - there is no more conservative argument than censorship “protecting the children”, and in this case, the children and vulnerable adults, whoever they are..




Cheers,

Steve

July 16, 2008

Cost of leadership

There is a lot of complaining over the Federal Government’s various schemes to reduce our carbon emission. Some of these are valid concerns, yet others are nothing more than short-sighted yapping of the unwashed. Here is a typical example of such a thing:



“if Australia cuts or carbon emissions by 50% it will not make any difference either as we contribute 1% and China and India are growing at a rate of 10% per year. They produce more Carbon in a day then we produce in a year. So why are we going to destroy our economy exactly again?”


This typified the majority opinion in my encounters with the Australian public online and off. It shows a marked lack of foresight and more than a little scare mongering. Firstly, our economy is hardly going to be destroyed because of emission trading. The European Union Emission Trading Scheme (EU-ETS) was implemented in 1st of January 2005 with the then 15 countries of EU as participants. Today 23 EU [1] members are participating in EU ETS. Do you really think the number of participants of EU-ETS would increase if emission trading destroyed economies?



So why should we implement emission trading when China, India, and the rest of South-East Asia (SE Asia) account for so much of the world’s carbon emission? The answer is two fold. First is the fact we are a First World country, an Enlightened Society, a World Leader. If we don’t do what we can do cut back on carbon emission, then how can we expect developing countries like China and India to do so? Secondly, countries like China and India have such large manufacturing bases because of us. First World citizens demand and consume products which are produced in factories based on South-East Asia. It is our demands which creates industries in in SE Asia, our demand that China and India account for such large percentage of global carbon emissions. United States of America emits more carbon dioxide per capita than any other nation, followed by Saudi Arabia and you guessed it, Australia [2]. In other words, Australians are the world 3rd largest carbon dioxide emitters. So when you combined add two and two together, it becomes absurd to suggest we simultaneously demand cheap products from countries like China and India and that they cut back on carbon emissions, while we do nothing ourselves.



The Kyoto protocol is often branded as a toothless tiger because of lack of political will. Yet when political will is exercised, the masses complain about the cost. Wake up people of Australia - only First World countries like ours can afford to exercise political will on such a scale and on this subject. As consumers we are the ultimate cause of carbon emissions, and as a world leader we need to be the ones who take the first step. Emission trading will cost us - see it as the cost of leadership, the cost of doing something proactive to ensure our future on this planet. If we balk at the cost, then we are in no position to ask China or India to cut back on their carbon emissions and absorb the resulting losses.



Cheers,

Steve

unoffical libfg repository

I have set up an unofficial git respository for libfg patches and new swig generated python interface, as Gavin Baker (the author) appears to be busy with other things. This is a maintance only repository as far as libfg goes - I don't plan on adding any more features (since all the ones I need are there already). I will however work to produce a more pythonic interface to libfg, as the swig generated interface is a straight port of C api into Python.



Currently the repository contains the following fixes and enhancements:



  • RGB565 and RGB555 patch by Adalbert Prokop

  • fg_new_compatible_frame patch by echoline

  • mmap fix by me

  • swig generated Python interface by me



If you have a patch against libfg, please post it at the libfg project's page first, and then to me if Gavin does not respond. I do not intend to take over development of libfg, and it is my hope Gavin will in the future make this obselete/redundant.




Cheers,

Steve

July 08, 2008

Evolution of a circuit layout

Half way mark to a 4 channel motion controller. Version 3 of the layout seems to work well and was relatively easy to duplicate by eye. In fact I hardly used the schematic at all.

The new lead free solder (1mm) I am using is much too thick for my liking, I ended up using more solder than I normally would, and made some unintentional bridges which caused problems. That and one of the diodes were wired in reverse.

I really need to find some sub millimeter lead free solder - no one seems to stock them here in Australia :-|

Cheers,
Steve

July 05, 2008

Another holiday, another webapp

Thats right, another webapp! This time using google's app engine, so feel free to abuse it, somewhat :P



Rank'em is its name, and it basically lets you create a collection of Things then allow other people to rank each Thing against each other, producing an overall ranking of Things.



Have fun and let me know what can be done better.




Cheers,

Steve