Linux
Linux is an Open Source "Unix like" operating system available for a variety of hardware architectures (like i386 or AMD64). We are using Linux mostly on our students and stuff workstations and as the operations system on all our number crunchers.
Configurations - Hints for configuring Linux
Applications - Using some selected Linux applications
Software - List of available software on Linux (you can also use the comandline tool sepp)
ISGLinux - The ISG.EE Linux distribution
Distributions - Other Linux distributions