The above article contains several links to other articles that can provide a better understanding of what all the Linux choices and piece-parts are about. If you are curious, I suggest browsing the following articles in this order:
What Is A Linux Distro
A brief discussion of the concept of a Linux distribution
8 Pieces of Software That Make Up Linux Systems
This one covers in more detail the components of a distribution.
Linux Desktop Environments
This one covers various desktop environments that may be part of a distribution or may be pulled into a Linux installation. A Linux user may choose from among several distributions that are identical except for the desktop environment. Those who wish to use or try Linux on older hardware are often advised in web articles or postings to consider the light-weight desktop environments Xfce or LXDE. Some Linux veterans have actually set up their installations to enable switching between two different desktop environments. Most users probably try out several distributions, running from a live CD (slow) or a USB flash drive before choosing one or more to install in some permanent fashion.
The web site Distro Watch is my favorite for finding and exploring different distributions. You can browse the main page or use the search filters to find candidate distributions for certain needs. You'll also note that the site catalogs BSD and Solaris, in addition to Linux. For those who are curious, this article explains the difference between BSD and Linux. The use of BSD as the base of Mac OS X is mentioned.
John
