59. About Updating and Adding Applications to NLD

NLD provides two different GUI tools that make it easy for you to update programs, add software, and remove software. YaST, the NLD administrative configuration tool, allows you to add and remove software from your NLD installation (add software using the NLD installation disks or updates) and also makes it easy for you to run a system update and apply patches to your system.

Three icons in the YaST GUI window (when Software is selected in the left pane) are of particular interest:

• Install and Remove Software This tool allows you to view the software installed on your system from a particular installation CD or DVD. You can also use this tool to remove software from the system.

• System Update This tool allows you to connect to Novell's update servers and update your system software.

• Patch CD Update This tool allows you to install patches to your system from a patch CD or DVD.

Key Term

Patch A patch is a software update to a particular system or software file that resolves issues or tightens security.

To access YaST you must know the root password. This makes sense because even though YaST makes it easy to add and remove or update software, there is always a level of risk involved related to maintaining the integrity of your system. Think carefully before adding and removing software.

Another tool that makes it easy to quickly update your NLD software and search for other software packages on the Novell software update servers is Red Carpet. Red Carpet provides a GUI window where you can view available updates, view software installed on your system, and search for available uninstalled software on the NLD update servers. To use Red Carpet you need to know the root password.

YaST provides easy access to software installation and system update tools.

Red Carpet makes it easy to update your system from online software resources.

Note

If you are running a free or "sample" version of NLD, you typically get updates for only a limited period of time. A "full-blown" purchased version of NLD provides a much longer time frame for updating the system software, software applications, and applets. In either case, you must activate the updates for your system for Red Carpet to work properly.

One other thing that we need to discuss before looking at Red Carpet and then YaST is the issue of dependencies. Let's say that you want to install program A, but there is a dependency for program B. This typically means that program B must also be installed on the system for program A to actually function after you install it. In some few cases, programs have negative dependencies, meaning that you can't install both the programs on the system if you want either one to run.

Key Term

Dependency A necessary software module for a program to run on the Linux system. Linux applications and applets require other software modules and files to be installed before the application or applet will run.

Dependencies for a software package must be met for it to run after installation.

So the question arises: When should you use YaST and when should you use Red Carpet to install and update software? They both share some of the same capabilities.

YaST works best for adding software and patches to your system from CDs and DVDs. YaST actually has a better tool than Red Carpet to check whether all the dependencies are met for a package you want to install without having to view a list of dependencies.

Red Carpet is easy to deal with in terms of performing system updates because an indicator appears on the top panel when system updates are available. Red Carpet (at least in my opinion) also makes it easier to quickly view all the software installed on your system, and with just a couple of clicks you can remove or add a package.