Install from bz2 Package
Before installing the compiler, the environment variable $TOOLROOT  should be set properly. As the name suggests, this variable specifies the root of the installation hierarchy. You can set it to anywhere you have write permission. For example, in GNU BASH this may be done with the following command: may set this variable by adding this command to the $HOME/.bash_profile file:

    export TOOLROOT=$HOME/mycompiler

After that, run 'source $HOME/.bash_profile' to make the change effective.  Now, to complete the installation:

1. Expand open64-4.2.1-0.ia64.tar.bz2 with the command:

    tar jxvf open64-4.2.1-0.ia64.tar.bz2

2. Run script 'INSTALL.sh'

The C, C++, FORTRAN compilers are now available in folder  $TOOLROOT/bin. They are opencc, openCC, and openf90 respectively.
 
Install from RPM Package
1. To install the compiler from rpm:

    rpm -ivh open64-4.2.1-0.ia64.rpm

This command will install the Open64 compiler to /opt/open64. The C, C++,  FORTRAN compilers are in folder /opt/open64/bin.
2. To install the compiler to another location:

    rpm --prefix=/path/to/folder -ivh open64-4.2.1-0.ia64.rpm

Then the compiler will be installed to /path/to/folder