Mac OS X

Manually install the Java Runtime Environment

On October 16, 2012 Apple has started to disable Java applets in Mac OS X 10.6, 10.7 and 10.8:

If you installed any maintenance updates for Mac OS X after that date, Java applets won't work.

You have to download and install the Java Runtime Environment yourself from


Set Prefered Language

According to this is simple:

To change your language preferences go to Tools > Options (Windows) or Edit > Preferences
got to tab Content. Down right of Languages click on the button Choose.

* You can add languages to this from a (long) pre-defined set, and Firefox will send all the languages you choose with the Accept-Language header in the order in which you arrange them.
* You can't create custom language tags using the standard interface. (You can, however, via about:config, using intl.accept_languages if you are geeky enough.)

On Mac OS X the language sent is that specified in the OS X system language preferences. To change those preferences go to System Preferences > Language & text > Language. You can have a long list of languages in this dialog box, but Safari will only send the top item with the Accept-Language header. You can't create custom language tags.

On Windows, you can't change the language sent by Safari. The language sent with the Accept-Language header is derived from your system settings.

Google Chrome
To change your language preferences go to Options (Windows) or Chrome > Preferences (Mac OS X), and select Under the Bonnet > Web Content > Languages & Spellchecker settings.

You can add languages to this from a pre-defined set, and Chrome will send all the languages you choose with the Accept-Language header in the order in which you arrange them. You can't create custom language tags.

On Windows you can change your language preferences at Menu > Settings > Preferences > General > Language > Details (button).

Dropbox - Storing and sharing files in the cloud

Dropbox is a web-based file hosting service which uses cloud computing to enable users to store and share files and folders with others across the Internet using file synchronization. You can download it at

Dropbox can be installed on Windows, Mac OS X, Linux, iPhone, iPad, Android devices and more. After creating an account and installing, you will find a folder called "My Dropbox". All files in this folder will be synchronized seamlessly to every other device that has Dropbox installed. If you can't install the client, you can still use the web interface at - just log in with your username and password in the upper right corner.

Dropbox also offers a version history and sharing features. Using the version history you can easily revert back to previous versions. The sharing features are great for collaborating on files and folders.

Enabling Java in Firefox 3.6

1. Since Firefox 3.6, the Java is treated just like all other plugins and no longer has a enable check box in Tools > Options > Content. We can enable or disable Java plugin (and also all plugins) via Tools > Add-ons > Plugins.

2. What if the Java plugin does not appear in Tools > Add-ons > Plugins (you can also checked it by typing about:plugins in the address bar). It means that you have to install Java (before you can use Java in your Firefox). Since Firefox 3.6 and later versions you need the Next-Generation Java™ Plug-In present in Java 6 U10 and later.
These are how you can do it in various operating system (taken from

On Mac OS X
You can use the Mac OS X Software Update feature to update Java.
Note: The Java Embedding Plugin is bundled with current Mac distributions of Mozilla browsers, including Firefox and SeaMonkey. This utility allows browsers other than Apple's Safari to use the most recent versions of Java on Mac OS X.

On Linux
1. Download the Linux version of the Java software.
2. When the download is finished, execute the .bin file as root and follow the prompts.
3. When the installation has completed, run this command in the plugins directory of your Firefox installation:
ln -s /your_path_here/java/j2re1.5.0/plugin/i386/ns7/
4. Firefox 3.6 and later need the Next-Generation Java Plug-In
See Manual Installation and Registration of Java Plug-in for Linux (at
Run this command in the plugins directory of your Firefox installation to create a symbolic link to the Java plugin (replace xx with the current Java version):
ln -s /usr/your_path_here/java/jre1.6.0_xx/lib/i386/

On Solaris Intel
1. Install the Solaris Intel version of the Java JRE or SDK.
2. When the installation has completed, run this command in the plugins directory of your Firefox installation:
ln -s /your_path_here/jre/plugin/i386/ns610/ .

On Windows
Automatic update: The Java Update feature automatically checks for updates in Windows 2000/XP/Vista at scheduled intervals and notifies you when an update is available so that you can install it. If you have administrative privileges, you can also check for updates yourself and install them from the Java Control Panel (Start -> Control Panel -> Java -> "Update" tab).

Manual install or update:
1. Go to and click on the Free Java Download button.
2. Click on the Download Now button to start the online installation.
3. Close and restart your browser after the installation is complete.
If you prefer an offline installation, go to the Java SE Downloads page (see above for links) select the Java SE Runtime Environment (JRE) and save the offline installer (e.g., "jre-6u10-windows-i586-p.exe" for JRE 6 Update 10) to any convenient location, close your browser and run the installer.

Important: Previous to JRE 6 Update 10, installing or updating to a newer Java version would add a new Java Runtime Environment (JRE) instead of replacing the existing version. For example, if you already have JRE 6 Update 7 installed and later install JRE 6 Update 10, you would end up with two JRE versions installed in separate directories. You can remove older Java versions via Windows Control Panel "Add or Remove Programs", to save disk space and because older versions often contain security vulnerabilities.

Starting with JRE 6 Update 10, future Java updates will patch the current version by default instead of adding an additional version. For example, if you previously installed JRE 6 Update 10 in the C:\Program Files\Java\jre6 directory, and in the future you install JRE 6 Update 14, the version 6u14 installer does not create a new directory. Instead, it updates the pre-existing "jre6" directory with the new 6u14 content (JRE Update 10 will no longer exist). This will prevent an accumulation of unused and potentially insecure older JRE versions.

Using Boot Camp to run XP and MacOS on the same computer

Boot Camp is software included with Mac OS X 10.5 Leopard that lets you run compatible versions of Microsoft Windows on an Intel-based Mac.I will be guiding you guys through how to setup Boot Camp in Mac OS X Leopard or Snow Leopard. Boot Camp is a utility that comes with every new Macintosh and can run on any Intel Macintosh. It allows you to natively boot and run Windows XP (SP2 or later), Vista or Windows 7 (Not officially supported yet). Here goes the tutorial:Step 1: Navigate to Applications>Utilities>Boot Camp Assistant and open it. Read the introduction and click continueStep 2: Pick a partition size and select “Partition”. Allow the assistant to partition your hard drive for you.Step 3: Follow the rest of the Boot Camp Assistant instructions, ending with inserting your Windows Installation DVD/CD.Step 4: For the rest of the steps in setting up and installing Windows on to your Mac, follow this Apple Boot Camp tutorial: 

How to use Git DVCS (distributed version control system) and GitHub to effectively collaborate on an open-source software project

Here are the basic/central steps to take.

  1. Register an user account at
    (In this example we suppose the user is called hugo and has as email address.)
  2. Create a repo on GitHub.
    (We'll call it foo-project here.)
  3. Install Git (e.g., on OS X with MacPorts).
    sudo ports install git-core
  4. Set Git user email.
    git config --global
  5. Init repo.
    cd foo-project
    git init
    git add .
    git -m commit 'First commit.'
    git remote add origin
    git push origin master

Congrats, your project is ready to be used with Git and GitHub now.
Here's a good overview of Git and here are some useful notes with common commands.

Have fun! :-)

Installing and using iCal Server

  1. When configuring Mac OS X Leopard Server, three options are available: standard, workgroup and advanced configuration. Advanced is to be used if an iCal Server shall be hosted
  2. A correct defined DNS is necessary.
    • In the program ServerAdmin select the service DNS
    • In the program ServerAdmin in the DNS part add a new primary zone (e.g.
    • Add a record for the computer hosting the iCal server (e.g. server results in the fully qualified name of ""
  3. Users have to defined in Open Directory (a kind of LDAP server) that can access the iCal server.
    • In the program ServerAdmin select the service Open Directory
    • In the program ServerAdmin in the Open Directory create a master directory
    • A kerberos server for authorization will be created if Open Directory is started. The Kerberos realm in our example is "SERVER.TECHSCREEN.AT"
    • If the state of Kerberos is "not working" after start of Open Directory then the DNS was not configured correctly
  4. Add a user
  • In the program workgroup manager add a user that may have access to the iCal server (e.g. student with password "Reine")
  • In the Advanced tab enable calendaring for this user
  • Enabling iCal Server
    • In the settings of the programm ServerAdmin select the service iCal
    • In the programm ServerAdmin in the iCal part select a domain name such as ""
    • Do not select SSL unless you have a real certificate, otherwise no access to the server is possible
  • Access from a Mac OS X client to the iCal Server
    • In the program Directory Service add the name of the server (i.e.
    • In the iCal program select settings|accounts and add user (e.g. student) and the password
    • Now a calendar is shown in iCal. The name of the calendar can be changed and new events can be entered. Every other user that knows about the user name and the password can now access this calendar. This should be also possible fro other programs supporting iCal and CalDAV



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