For over 20 years, Knoppix has been the premier portable operating system and rescue disk for Linux users. Although its packages are drawn from the Debian repositories, and contributors add to its hardware support, the bulk of the work on the distribution is done by German electrical engineer Klaus Knopper (Figure 1), an independent consultant and instructor at the Kaiserslautern University of Applied Sciences. Over the years, Knoppix's hardware support has increased, features have been added and dropped, and its original purposes have been joined by ADRIANE (Audio Desktop Reference Implementation and Networking Environment), a desktop designed for the sight impaired with input from Klaus's wife, Adriane Knopper (Figure 2). All of which shows how this passion project is evolving with the times and is as important as ever.

"When I started studying electrical engineering in the late '80s," Klaus Knopper says, "my plan was to build electric cars and solar power plants. Apparently, this vision was just a little too early, so my interests turned more towards networking software and the possibilities that appeared with the Internet." At the time, free software was how Unix-like systems were taught, with exercises done with the GNU shell and compiler collection, using the GNU/Linux, BSD, and Hurd kernels. Knopper was among the students who founded a Unix working group, which eventually went on to organize the LinuxTag expo.

A few years later, Knopper encountered the Linuxcare Rescue CD, an 18MB business-card-sized CD with the Linux kernel and a command-line rescue tool. Knopper recalls, "I thought that a full CD-sized operating system with all the applications I use frequently, including a graphical desktop, data forensics, and TeX and other favorites would be extremely practical for travelling without a computer, using publicly available computers while still being able to use my personal software collection without installation."

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