Linux and Free Software
The GNU/Linux operating system

The kernel
Linux
Runs on Intel, Sparc, Alpha, M68K, PowerPC, ARM
Written in C and assembly language
Supports symmetric multiprocessing (SMP)

The rest of the operating system
GNU tools, from the GNU project
Assembler, compilers, linker
Not specific to Linux
Third party tools
Free (GTK) or proprietary (Sun's JDK) software