Sonntag, 26. Februar 2012

Bob Marley - Soul Shakedown Party (Fort Knox Five Remix)

The right sound to start in the day:

Freitag, 24. Februar 2012

Xv6 - Unix-like OS in C for teaching purposes

Here's another one from my bookmark cruft: Xv6, a Unix v6-like OS rewritten from scratch (in C, with a little help of Assembly) to teaching operating systems:

About Unicode and Character Sets

Just dug out some older blog article from Joel Spolsky which - in my eyes - really became a classic and a must-read for every programmer out there:

The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!)

Don't know this one yet? Read it, you won't regret it! :-)

Mittwoch, 22. Februar 2012

Paper.js Vs. Processing.js Vs. Raphael

Some while ago I toyed around with Raphael.js and was quite amazed by it -- today there's a nice article over at Smashing Magazine which compares the alternatives Paper.js and Processing.js to Raphael, check it out: Web-Drawing Throwdown: Paper.js Vs. Processing.js Vs. Raphael

Montag, 13. Februar 2012

How to fold a suit, pants and shirt to go in a suitcase without wrinkling

Sonntag, 12. Februar 2012

AMPPS - Try online software with no remorse

Some of you maybe already heard of it or even have used it so far, but I just stumbled over AMPSS, a free package (or better: software stack) containing over 250 software appliances such as Wordpress, Joomla or (my favorite!) Tine 2.0 in a ready-to-go state using the well-known Apache, PHP, MySQL combination.

Don't use this for production systems of course, but AMPPS is compelling and very time-saving when you want/need to evaluate online system like the ones mentioned above. Give it a try!

Donnerstag, 9. Februar 2012

Funky Star Wars Mixtape

May the funk be with you!

Samstag, 4. Februar 2012

[Update 4] Ubuntu + TP-Link TL821Nv3 / TL822N v2.0

After I upgraded my Ubuntu 11.04 to 11.10 due to the upcoming 12.04 version (which I won't upgrade to anymore because of their Unity crap, just a personal rant btw) I had massive problems with my not-so-old TP-Link TL821Nv3 wireless USB-stick which worked fine most of the time all day long.

Now, for those of you who also have problems with this stick: Be aware that there are different versions of  TL821N / TL822N around: On the retail package there are very small version numbers (such as v3 or v2.0) printed on.

Okay, so after having that much trouble with my formerly bought TL821Nv3, I decided to go with the TL822N because of reports that this stick has a slightly different chipset on it. A few days later the new stick arrived and I did some basic lookup using "lsusb" on it: Crap, the very same chipset (0cf3:7015, ath9k_htc) on it as on my former TL821Nv3! They must have changed the chipset between revisions, because older reports claim they used a different Aheros chipset on this stick before. Bad luck for me move on.

After doing some more research I thought it would be worth trying out the latest ath9k_htc driver from the Linux 3.3 kernel (Ubuntu's stock kernel with 11.10 is btw) -- so digging further into the Linux Wireless Project. Here you can get a source package with the latest (stable?) drivers which come with the stated kernel. For getting a list of all current releases, take a look here.

So - finally, after a lot of text - here comes a small how-to for building and installing the latest ath9k_htc driver from the Linux 3.3 kernel on your Ubuntu (also should work on the Linux Mint/Kubuntu/you-name-it equivalents):

  1. First, verify that you're still using the old ath9k_htc module by doing a "modinfo ath9k_htc". The old driver's path in "filename" should point to "3.0.0.something" and the path should contain "kernel/drivers".
  2. Do a "sudo apt-get install --reinstall linux-headers-$(uname -r) build-essential" for installing the required build tools and Linux headers.
  3. Download the latest Linux Wireless package (at the time of writing this is 3.3-rc1-2) by doing a "wget".
  4. Unpack it: "tar xvjf compat-wireless-3.3-rc1-2.tar.bz2".
  5. Go into that directory: "cd compat-wireless-3.3-rc1-2".
  6. Select the correct driver(s) to build by doing a "scripts/driver-select atheros".
  7. Finally, build the stuff by just doing a "make".
  8. After the stuff got built, install the newly built drivers and unload the old ones with "sudo make install && sudo make wlunload".
  9. Verify again that now the new driver got loaded by doing a "modprobe ath9k_htc".  In the filename field the path now should contain "updates/drivers" instead of "kernel/drivers" (as pointed out in step 1).
Update: If connections are still dropping, try disabling the power management of the USB stick by doing a "sudo iwconfig wlan0 power off", where "wlan0" represents your configured wireless device bound to the USB stick.

Update 2: After some more reading about the TP-Link sticks I get the impression they appear to have an overheating problem. Some users even opened their stick cases and added a small passive cooler to the main chip on the logic board. Another option that might help to cool down the stick a bit when processing a lot of wireless traffic is to add "options ath9k_htc nohwcrypt=1" to a newly created file named "ath9k_htc.conf" in the directory "/etc/modprobe.d/". After that just reload the modules or simply do a reboot of your machine.

Update 3: In case the above still doesn't work for you all day long (that's how it is for me -- it works okay, but not through and through yet), here's a simple sudo script called "" which does all the teardown work for you to re-initialize all the stuff to get it back working again:
ifdown wlan0
rmmod ath9k_htc
rmmod ath9k_common
rmmod ath9k_hw
rmmod ath
rmmod mac80211
rmmod cfg80211
pkill wpa_supplicant
ifup wlan0
If, for whatever reason dmesg tells you "Registered led device: ath9k_htc-phyX", where "phyX" in a higher number (let's say > 10) then there is little chance to get the damn stick working again without reloading the modules mac80211 and cfg80211 (which does the script above already).

Update 4: Seems like there were a lot of changes in the 3.4-rc3 compat package (see Changelog). While the USB stick still is not running 100% perfect I'm giving 3.4-rc3 a go on my not-yet-updated Ubuntu 11.10. Go an grab the new compat package here.

Let me know if/how it's working out for you!

Good luck!