I’ve finally managed to find a little tool that can give you 1:1 mouse/pointer movement, just like you can on Windows (with the help of some regtweaks and system file patchers).

Download this Preference Pane and run it: MouseAccelerationPref11c

Use these settings:

I know it says ‘Inverted’ on -6.0x, but it’s actually 1:1 non-inverted

Luckily there are some nice tricks you can use to make a remote kernel upgrade as safe as possible.

First, make sure you have a valid kernel. Copy the .config of an old kernel and ‘make oldconfig’ to make it work on your new-to-be-compiled kernel.

Second, make the kernel using the ‘make-kpkg’ package, don’t forget the –initrd parameter if you need it.

Third, after installing the kernel package, don’t forget to check if the initrd image got generated. For some strange reason Debian won’t generate this even after building with make-kpkg –image, you can read more about that here. You basically need to copy a file from ‘/usr/share/kernel-package/examples/etc/kernel/postinst.d/initramfs’ to ‘/etc/kernel/postinst.d/initramfs’

Fourth, you need to configure Grub2 so it uses a kernel boot option which makes the kernel restart if it can’t boot for some reason. To do this with Grub2, open /etc/default/grub and add “panic=5″ to GRUB_CMDLINE_LINUX_DEFAULT, like this:

GRUB_CMDLINE_LINUX_DEFAULT=”quiet panic=5″

Fifth, Grub2 needs to be told to only boot the new kernel once, so in case the new kernel panics, it automatically restarts using a kernel you know works (your current one perhaps). Else the ‘panic=5′ we set earlier will only lead to a reboot loop.

To do this open /etc/default/grub and change GRUB_DEFAULT to saved, like this:

GRUB_DEFAULT=saved

To configure ‘reboot-once-into-new-kernel’, we need to do two more things, first we need to tell Grub2 what your working, safe kernel is. Check /boot/grub/grub.cfg for the name of this kernel, but don’t change anything in this file.

My safe kernel is called: ”Debian GNU/Linux, with Linux 2.6.32-2-686″, which I can set as the default, safe, kernel with this command:

grub-set-default ”Debian GNU/Linux, with Linux 2.6.32-2-686″

Now we have to tell Grub to reboot once into the new kernel, again we need the name of the new kernel, mine is ”Debian GNU/Linux, with Linux 2.6.32-example”, use this command.

grub-reboot ”Debian GNU/Linux, with Linux 2.6.32-example”

Don’t worry, this won’t reboot your machine.

The final step is to generate a new /boot/grub/grub.cfg, else all the things we just did won’t have an effect

update-grub

Now you’re ready to reboot, good luck and fingers crossed. After a succesful boot, you can set your new kernel as the default using the grub-set-default command

grub-set-default ”Debian GNU/Linux, with Linux 2.6.32-example”

It’s an Android based phone so it’s easy to customize and there are a lot of great apps available for it.

However, HTC’s default firmware is a bit sluggish. Luckily there’s a solution. It takes 5 minutes and besides speeding it up, it also ‘roots’ it. ‘Rooting’ an Android phone allows a user to do basically anything he wants with the phone.

Here are the steps (by Paul of MoDaCo)

- Download the custom ROM, and copy it to your SD card (modaco 2.2 core)
- download this file (http://content.modaco.net…copatchedrecovery-1.0.zip) and extract it to your PC or mac
- open a command prompt to the directory containing the extracted files
- type the following commands (prefix each command with ./ if you’re on a mac)
- adb shell reboot bootloader (wait for device to reboot into bootloader)
- fastboot boot cm-hero-recovery.img
- Select ‘nandroid backup’ from the menu to do a backup
- If you copied the custom rom as update.zip, select ‘apply sdcard:update.zip’, else select the option below.
- all done

Playing back 1080p content however, was still a problem. I was never able to get smooth playback with mplayer. Only the xbmc videoplayer could play 1080p smoothly on my system. XBMC is not an option due to the WAF, it has to be something that runs from MythTV.

Fooling around with coreavc-for-linux (I love CoreAVC on Windows) got me nowhere. Recompiling, tweaking and updating mplayer/nvidia/xorg, nothing seemed to work.

Until I tried a new version of mplayer from the Debian Multimedia repositories. The mplayer version in that repository has support for a new feature in the linux nvidia drivers that (finally) allows video decoding on the GPU.

The easy steps to get this to work:

• Download and install the new nvidia linux drivers (180+)
• Add the Debian Multimedia repository to your sources.list
• Install mplayer from the new Debian Multimedia repository
• Start mplayer with ‘-vo vdpau -vc ffh264vdpau’

More than a year of tweaking and tinkering made redundant by these easy steps, excellent!

I had the following error whenever I tried to use ‘script/console’ (script/server and rake worked fine)

require ‘mysql’

MissingSourceFile: no such file to load — mysql
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require’
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in `require’

Turns out I had multiple versions of RubyGems installed on my Macbook. The error message already spoils it by saying rubygems in /System/Library/Framework/ is being called, while I actually installed rubygems manually in a different folder.

To prevent these kind of problems in the future I simply deleted the entire Ruby.framework directory and use the manually installed versions instead.

I’ve been using my new Macbook for a whopping two days now, so I think it’s time to share some of my early impressions.

First of all, I’m not a typical computer user. I’m picky, opinionated and totally unreasonable when it comes to my requirements for an Operating System. Before my Macbook my setup consisted of:

• Desktop PC, Windows XP: Used for gaming mainly, also editting photo’s and as a ‘fat client‘ for Putty
• Laptop, Ubuntu: Used for work and midnight-coding. Purely a development tool for developing Ruby on Rails webapplications, accessing icanhazcheeseburger.com and other important work stuff.

The Windows XP of my desktop PC is a necessary evil. Games for Linux and Mac OS X are rare and my girlfriend still has an emergency Windows-account she can use whenever her Windows XP laptop refuses to work properly. Simply put: I’m stuck with XP for my desktop and I don’t really mind (a lot).

The laptop running Ubuntu belongs to my employer. Ubuntu is an excellent platform to develop Ruby on Rails applications, the huge Ubuntu repository contains recent version of all necessary tools and the apt package manager is simply unmatched on any platform. To isolate myself from outside influences during coding sessions I use a closed headphone and Amarok (a rather bloated KDE program, so I can’t bitch about iTunes without being an ever bigger hypocrit). Pidgin provides me with access to nearly all IM networks, while TwitterFox keeps me in touch with fellow twitterati.

My new Macbook is supposed to replace the Ubuntu laptop and serve as an alternative to my desktop at home. Here are some of my initial thoughts regarding this migration:

It just works

It doesn’t.

Ok to be fair, a lot of stuff just ‘works’, I am however spoilt by Ubuntu 8.10 which also ‘just works’, it just fails to work on different points compared to Mac OS X. OS X fails to ‘just work’ as a Ruby on Rails development environment, sure it comes preloaded with Ruby on Rails, but it has ancient version of Rails, Ruby and Rake and this completely screwed me over while trying to convert my fresh Macbook into the ultimate web-development machine.

Multimedia support is not as good out of the box as Ubuntu. In Ubuntu all the codecs you need are in the repository and are a easy to install. To be fair, this is only since the 8.x branch of Ubuntu. For OS X I had to find a bunch of codecs from questionable vendors (I’ll never trust the DivX corporation after their bloated Windows installers) before I could get my movies and series to play in Quicktime.
Speaking of horrible failures, I don’t see how anyone could enjoy Quicktime. It’s completely inadequate compared to Zoom Player on Windows or MPlayer on Linux. I’m planning to replace it by something decent ASAP. Preferbly something pretty like XBMC or the OS X specific port of this brilliant project.

Package management? What’s that?

Mac OS X understands package management just like this girl understands “PC’s”. Not a clue. Everything application you install has it’s own auto-update function and the built-in Software Update is about as useful as “Microsoft Update”. Which is not bad, it’s just not as great as Ubuntu’s software updater.

MacPorts < apt

MacPorts is similar to Debian/Ubuntu’s APT. It provides an easy way to install and update software for your Mac. Unfortunately it’s more like Gentoo’s ‘emerge‘ and less like Debian’s ‘apt-get’. Everything you install has to be compiled first, and if you want to install something with fancy graphics you’ll have to wait for an hour while the X window manager gets compiled (ok, this is only the first time).
Fortunately it does what it’s supposed to, it just takes quite a lot longer than APT and the repository of available software is tiny compared to Ubuntu’s insane heap of FOSS. For example, something like ‘htop‘ is not available on OS X, but luckily there’s the Activity Monitor GUI to offer some compensation.

OS X < GNU

Mac OS X implements all the usual Unix tools. Things like find and grep. These are kinda different to the GNU-tools I used on my Ubuntu laptop and Debian servers. As far as I can tell after these few days of use, the Mac OS X versions are inferior to their GNU-siblings. I’ll have to get used to this or find alternative tools

So much for the bitching, here are a few things I do like:

It just works

A lot of stuff works just fine out of the box. The prepackaged software gives Ubuntu a good run for it’s money. Also, it’s obvious OS X is more popular than Linux. Quite a few software products offer a reasonable up-to-date version for Mac. Skype for example has a Mac version which is nearly identical to the Windows version, while the Linux version is lacking a lot.

Basic hardware compatibility is not an issue

If you’re the only one making hardware for your OS (or is it the other way around?) it’s easy to make that hardware supported in the OS. While the linux kernel provides support for nearly every graphics card, sound card, IDE controller and toaster made in the history of electronics, OS X only has to support the very limited set of hardware used by Apple. And to Apple’s credit, it does this very well. Unlike Linux they don’t have to work around crappy vendors breaking standards that crash your laptop after a resume-from-standby. As a result, stuff like suspend-to-ram and connecting multiple monitors works really well and quickly.

It’s a lot like Linux

Overall I feel quite at home in OS X already. I was able to set up a proper development environment during a single evening, inspite of the great efforts of MacPorts to keep compiling very large bits of software. During the coming weeks I expect to find a lot more things that are different/worse/better in OS X compared to Ubuntu but the past few days have made me optimistic about the chances of OS X being the only OS on this Macbook. I originally intended to go for a triple boot setup; Windows XP, Ubuntu and OS X, but I think I’ll settle for installing Windows XP in a VirtualBox. Not because I like XP that much, but for testing web-application in the worst browser ever made and it’s younger brothers.

That’s it for now, I’ll probably write a new post in a couple of weeks, because I’m sure OS X has plenty of annoyances and amazements left in store for me.

Unlike the old Livebox, you only get limited access to forward ports and change the wifi SSID and password. Even DynDNS support, which was perfectly usable in the Livebox, is disabled.

Looking for a way to disable the built-in DHCP server and change the default IP address of the Speedtouch 706 I tried flashing the device with the original firmware instead of the locked one. However, the firmware updater refuses to flash because of incompatibility.

This didn’t stop me and using TFTP I tried forcing the flash, but again, this didn’t work.

After some googling I came across a vulnerability in the Speedtouch 780, that allows you to access any page of the webinterface, even the ones you shouldn’t have access to. Using this vulnerability it’s possible to download the modem’s configuration, change it in a text editor and upload it again.

Thanks to this vulnerability I was able to disable the DHCP server and change the symmetric NAT implementation to cone NAT. The default configuration makes it nearly impossible to play online games based on a player-to-player architecture. C&C3 and Supreme Commander are two games that use this technique to allow players to play against eachother. With the original configuration I was unable to connect to about 80% of players in Supreme Commander, now with the cone NAT configuration I no longer have any issues.

You can find instructions to download/upload the Speedtouch configuration here and you can find/replace these bits in the user.ini to get cone NAT instead of symmetric NAT:

connection bind application=CONE(UDP) port=0

connection appconfig application=CONE(UDP) timeout=0

ids config state disabled

The contestants

mod_rails (Apache 2.2.8)

Thin 0.8.0 (Cluster of 4 behind nginx 0.5.33, both TCP and Unix socket)

Ebb 0.1.0 (Cluster of 4 behind nginx 0.5.33)

Mongrel 1.1.4 (Cluster of 4 behind nginx 0.5.33)

The benchmark is the index page of Leef je doel, the hardware used is a Dell D830 laptop with a T7300 (speedstep disabled), 2GB of RAM and a 7200RPM harddisk. The page runs a few queries and also serves a lot of fragments from memcached.

The results

Performance

Like my previous test, Ebb comes out on top, closely followed by Thin.

Using the default Apache2 config supplied by Ubuntu, mod_rails shows performance equal to mongrel_cluster behind nginx. I’m sure that by tweaking the Apache config files, some performance can be gained.

Compared to setting up nginx and thin/ebb/mongrel, setting up mod_rails is a lot simpler. Have a look at their screencast to see how easy it is, if you have a working Apache2, you’ll have mod_rails up and running within minutes. There are some small issues with mod_rails at the moment, for a list, check mod_rails’ Google Code page.

During development we already prepared caching for all pages, mostly fragment caching. To expire cache that’s no longer current, we use sweepers that get called when something relevant is updated. These sweepers only sweep the caches that get outdated.

Because we were unfamiliar with caching and needed to see the result of our fragment caching, we used the file_store to store the generated caches. These files are stored on disk and this way you can easily see how many cache gets generated and what they contain.

Regex and file_store == FAIL

To sweep caches we used regular expressions, this way we could easily sweep all relevant caches at once. This was a bad idea, as you can read here and here

During the beta phase the size of the site steadily increased, more users, more goals, more groups. There was a noticeable delay whenever you updated/created something. A short investigation pointed to the cache sweepers as the culprit.

The file_store for cache isn’t exactly the fastest solution to store your cache, but when you combine it with regex sweepers, things really slow down. Whenever you do a regex sweep, all files in the cache directory get returned (not that surprising if you think of it), and the regex is run against it. So even if you do a sweep on /goals, it will also return files in /users and /groups. As a result, updating your profile could take 15 seconds.

MemCached

We’d been planning on moving the cache to memcached all along, so this seemed a good opportunity to do it. In the next few paragraphs I’ll describe how to install memcached, get the correct Rails plugin to make memcached play nice with fragment caching and how to configure your Rails application so it uses your memcache server.

Installation of MemCached on GNU/Linux

First of all, you’ll need to memcache daemon, assuming you have a nice linux distro you can:

sudo apt-get install memcached

This will work on Debian, Ubuntu and other Debian-based distro’s, on Gentoo you can

emerge memcached

The great thing about memcached is its simplicity, it requires no configuration after installation, just run it.

All about the gems baby

Now we’ll get the gem to allow Ruby to talk to memcache. There are two gems that do this, Ruby-MemCache and memcache-client. memcache-client is supposed to be faster, so I used that.

sudo gem install memcache-client

Plugin to play nice with rails

Rails’ fragment caching doesn’t work with memcached out of the box, you’ll need a plugin. This plugin also adds a nice bonus to the cache method in views.

script/plugin install svn://rubyforge.org/var/svn/zventstools/projects/extended_fragment_cache

Now we need to configure your Rails app to use the memcached server. You’ll need to edit your config/environments/production.rb

memcache_options = {
:c_threshold = 10_00,
:compression = true,
:debug = false,
:namespace = 'yourappname_or_anything_you_like',
:readonly = false,
:urlencode = false
}
CACHE = MemCache.new(memcache_options)
CACHE.servers = '127.0.0.1:11211'
config.action_controller.fragment_cache_store = CACHE, {}

That’s all folks!

That’s it, you’re all done, the ‘cache’ method in your views will now use the memcache server.

Oh wait, there’s an encore

But there’s more, using memcached you can set expiry times for caches. I edited the plugin for a default expiry time of 1 day. In vendor/plugins/extended_fragment_cache/lib/extended_fragment_cache.rb look for def write(key,content,options=nil)

def write(key,content,options=nil)
  expiry = options && options[:expire] || 1.day
  begin
    set(key,content,expiry)
    rescue ActiveRecord::Base.logger.error("MemCache Error: #{$!}")
    rescue MemCache::MemCacheError = err
    ActiveRecord::Base.logger.error("MemCache Error: #{$!}")
  end
end

You can change the 1.day to anything you want. To override this default behaviour, you can use the following code in your views

cache('goals/large_cloud', {:expire = 30.minutes.to_i})  do

This will make the cache called ‘goals/large_cloud’ to expire 30 minutes after it got created.

There are two important things to consider when you move to memcached

1. MemCached doesn’t support regex based expiry of caches. You need to manually enter every cache you want to expire. You can do this in some nice methods of course. Here’s ours for expiring the cache when a user gets updated.

def expire_user_fragments(user)
  fragments = %w[author_icon author_link side_block_friends ..snip...]
  fragments.each do |f|
    expire_fragment("user/#{user.id}/#{f}")
  end
end

2. Your application will fail when the MemCache server becomes unavailable. If you ever restart MemCache, or if it crashes (haven’t seen that happen yet), you need to restart your mongrel-cluster/thin/ebb.

3. When you restart MemCache, all cache is cleared, and you need to restart your mongrel-cluster/thin/ebb.

This guide only talks about fragment caching, over at Ben Curtis’ blog, you can read all about action caching.

Now what is Ebb?

The design is similar to the Evented Mongrel web server; except instead of using EventMachine (a ruby binding to libevent), the Ebb web server is written in C and uses the libev event loop library.

Connections are processed as follows:

1. libev loops and waits for incoming connections.
2. When Ebb receives a connection, it passes the request into the mongrel state machine which securely parses the headers.
3. When the request is complete, Ebb passes the information to a user supplied callback.
4. The Ruby binding supplying this callback transforms the request into a Rack compatible env hash and passes it on a Rack adapter.

The graph describes performance of a simple rack application and compares Ebb to mongrel, evented mongrel and thin. I’m more interested in performance with a Rails application and decided to do a benchmark for that.

In my benchmark I used the same application I used for my previous benchmark, only this time I benchmarked some extra pages.

Page 1 is a heavily cached page with few dynamic elements

Page 2 is a less cached page with a bit more dynamic elements

Page 3 is a non-cached page with an N+1 performance issue.

Ebb was tested using version 0.0.3, while Thin was on version 0.7.0. Both were run in a cluster of 4 behing nginx as a load balancer.

Interestingly Ebb managed to outperform Thin by about 10% on every page.