ROOT is an object oriented Data analysis framework.

As it requires a C++ compiler, it can be installed on MS Windows only if Visual C++ or Cygwin are installed. Here is only describe the installation with Cygwin. The installation itself could be easy, if you have everything needed on your computer. Otherwise.... All the problems I got while installing ROOT were caused by the lack of some components in Cygwin.

There are two ways to install ROOT : either try to install one of the pre-compiled executables or compile if yourself. Compiling is longer but safer. Installing pre-compiled executables requires you to use the SAME compiler version (e.g. do not run an executable pre-compiled with GCC 3.2 when you have GCC 3.3 in Cygwin)

1. First, let's assume that you have installed cygwin with all these packages. Installing Cygwin could last about 1 hour, but is easy to do. You can check your packages with this command line:

   cygcheck -c

   If some of them are missing, you easily can add them by re-executing the setup program of cygwin. For info, you can see here the output of cygcheck -c on my computer.
   
   
2. You can check your compiler version with the command line:

   gcc --version

   If you try to install ROOT from binary files, your compiler version should match the one of the binaries.
   [eg: WindowsXP/NT/w2000 with CYGWIN and gcc3.3 version 4.01/02]
   
   
3. ROOT should be installed into a directory whose name does not contain any blank character. Choose for instance C:\root4.xx but never c:\Program Files\... TIP: Naming the ROOT directory with its version number is useful to make several ROOT versions cohabit peacefully on the same computer (when upgrading ROOT version!), while letting you know what is where... I suggest to create the folder and then to copy the downloaded file into it.

1. After having downloaded the binaries (eg: root_v4.01.02.win32gcc.tar.gz) and moved it into the installation directory (eg c:\root4.01), untar it (with the good file name!) from this place:

   tar zxf root_v4.01.02.win32gcc.tar.gz

2. Finally, set the environment variables and it is ready to work!
3. If it is not working, it could be that you are missing something... This is why I suggest to remove the directory and try to compile ROOT yourself!

1. After having downloaded the source files (e.g. root_v4.01.02.source.tar.gz ) and moved it into the installation directory (eg c:\root4.01), untar it (with the good file name!) from this place:

   tar zxf root_v4.01.02.source.tar.gz

2. Then install it by typing these command lines.

   cd root
   export ROOTSYS=$PWD
   ./configure win32gcc
   make
   make cintdlls
   make install
   

3. Depending on your computer, make can take 1 hour or more ! Note that you should run make cintdlls and make install. Don't forget it!
4. Finally, set the environment variables and it is ready to work!

To finish the installation, some environment variables (ROOTSYS, PATH, LD_liBRARY_PATH) should be set (for instance, in the .bashrc file of your cygwin home directory, if you are using bash shell, or in the /etc/profile.d/root.sh file)

export ROOTSYS=/cygdrive/c/root4.01/root
export PATH=$PATH:$ROOTSYS/bin
export LD_liBRARY_PATH=$ROOTSYS/lib:$LD_liBRARY_PATH

You can check the value of these variables:

echo $ROOTSYS
echo $PATH
echo $LD_liBRARY_PATH

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• Axel's web site
• ROOT forum, when you search for Cygwin
• ROOT installation web page