3.4. How to install the software
The installation of the DIRSIG software is a simple task. The following sections attempt to provide some insight regarding how you should perform your installation.
3.4.1. Installation Layout
A standard DIRSIG installation has a directory hierarchy like the one pictured below:
3.4.2. Choosing the installation location
A common location for an installation that will be used by multiple users is in the /usr/local directory, however, this is a privileged location and root/superuser permissions will be required for installation. Unless the user installing the software has such permissions, arrangements with the system administrator for the machine will have to be made. The location of the installation is not important as long is it can be accessed by those users wishing to utilize it. For example, a single user may wish to install into a sub-directory under their home directory.
The recommended installation location for any release is /usr/local/dirsig-M.N.R, where M.N.R is the release number. For example /usr/local/dirsig-3.6.0. However, the release can be installed in any desired directory.
3.4.3. Unpacking the distribution
Each component is distributed as a gzip'ed tar archive that is expected to be unpacked from within the DIRSIG_HOME directory as we demonstrate in the following example.
3.4.3.1. Example Installation Process
In this example, we will assume that we are installing release 3.6.0 and that the installation directory will be /usr/local/dirsig-3.6.0. We will also assume that the installation components are located on a CDROM that is mounted as /mnt/cdrom. The target architecture in this example machine is a Linux-x86 machine. The following commands could be used to create the installation:
prompt> mkdir /usr/local/dirsig-3.6.0
prompt> cd /usr/local/dirsig-3.6.0
prompt> gunzip -c /mnt/cdrom/dirsig-3.6.0-base.tgz | tar -xvf -
prompt> gunzip -c /mnt/cdrom/dirsig-3.6.0-Linux-x86.tgz | tar -xvf -
prompt> gunzip -c /mnt/cdrom/dirsig-3.6.0-scenes.tgz | tar -xvf -
prompt> gunzip -c /mnt/cdrom/dirsig-3.6.0-docs.tgz | tar -xvf -
prompt> ln -s /usr/local/dirsig-3.6.0 /usr/local/dirsig
The last command makes a symbolic link called /usr/local/dirsig that points to the 3.6.0 installation. The use of a symbolic link is a useful approach to maintaining DIRSIG. When release 3.6.1 is installed at some time in the future, this symbolic link can simply be updated to point to the new /usr/local/dirsig-3.6.1 directory.
3.4.3.2. Making links to make program names constant
Since some users overlay subsequent releases of the model on top of previous releases, most of the programs in the $DIRSIG_HOME/bin directory have the version number appended to the filenames. This way when a new version is installed, the old executables are not overwritten. However, the user must know the full name of the executable (including the version number). When the model is updated, they will need to know that a new program with a different name can now be used.
To simplify this process, it is suggested that whenever a new release is installed a set of symbolic links are created in the $DIRSIG_HOME/bin. The follow list of commands assumes that the current release in $DIRSIG_HOME is version 3.6.0.
prompt> cd $DIRSIG_HOME/bin
prompt> ln -s dirsig-3.6.0 dirsig
prompt> ln -s make_adb-3.6.0 make_adb
prompt> ln -s cfg_edit-3.6.0 cfg_edit
prompt> ln -s mat_edit-3.6.0 mat_edit
prompt> ln -s tape5_edit-3.6.0 tape5_edit
3.4.4. Configuring the atmospheric database builder
One of the critical steps in the installation of the software, is the configuration of the atmospheric database builder, make_adb. This process is discussed in detail in The make_adb User Manual.