There can be many reasons of reinstalling Mac OS X on your computer system like:
1. Mac OS X is already installed on your drive but you want to upgrade it to latest version such as when going from Mac OS X 10.3 Panther to Mac OS X 10.4 Tiger.
2. You want to reinstall the same version just to eliminate some problems related to unexpected behavior of software or hardware which you have not been able to fix and your MAC OS X has damaged badly.
3. You frequently encounter errors which are related to shared library like:

“The application “app” could not be launched because of a shared library error:”<<app><Apple;Carbon;Multimedia><CFMPriv_QuickTime><>”

In these cases you left with none other option than reinstalling your operating system as you can’t afford these problems when you have to do lot of work on your computer system. The most primary way to reinstall it is to buy a CD or DVD and then install it on your computer system. Sometimes it also comes with your computer system.

But remember reinstalling an Operating system never plays a safe role as certain valuable data is at the verge of loss as when you reinstall any operating system; a formatting of your primary volume is required which could be the cause of data loss. So it is highly recommended to divide your hard drive into two or more volumes. There are various benefits like when you reinstall it then you have two ways of starting up your Mac from the same drive. If you’re having trouble with volume A, for example, and you need to restart from another volume to fix the problem, volume B is ready to go. You don’t necessarily need to seek out a CD or other external medium. Secondly all your data will not get lost as formatting will not be done from whole of the disk.

But if these precautions have not been undertaken by you, prior to occur of your problems which lead to condition of reinstallation or you have certain important data lying on the primary volume, then certainly you need not to worry about the data loss condition as recovery software are there for your rescue. These data recovery mac software are specifically designed to recover data from hard drive based on Mac operating system.

Stellar Phoenix Macintosh Data Recovery Software is one of the great software in this era. This software possesses a range of features that help you to recover data with much easiness and flexibility. This software can recover almost all file types including library files, document files and multimedia files and also from hard drives based on HFS, HFS+, HFSX and HFS Wrapper file systems. This software has a user friendly interface and its demo version grant you to have a look on the files that can be recovered.