Based on the Debian Linux distribution, Knoppix (see Figure 1) was one of the first Linux distributions designed explicitly to run from CD, and it remains one of the best. If you're burning Knoppix from an ISO download, you'll need a 700MB CD-R disk, as it won't fit on a 650MB CD-R. After booting the CD, you'll have the opportunity to pass special boot arguments to Knoppix. You can press F2 to get a list of boot options, but most users will just want to press Enter and use the default configuration. After booting, the KDE desktop environment loads. The desktop itself is both functional and visually appealing. A help screen loads automatically, giving links to Knoppix documentation stored locally on the CD. I was pleased to find my NTFS hard drives mounted as read-only disks on the desktop, allowing access to my Windows files. Knoppix also provided the best refresh rate for my monitor of any distribution I tested (85 Hz at 1024x768).
Figure 1 The Knoppix desktop.
Web browsing worked well with both Mozilla and Konqueror, the default KDE web browser. Pages loaded quickly and rendered accurately. Konqueror also serves as the file manager. Both the KOffice and OpenOffice.org suites are provided. Knoppix also includes a decent mix of audio, video, and graphics applications. SSH and HTTP server modules can be started on demand, offering a great way to experiment with Linux as a server. Knoppix even includes security tools such as Ettercap, Airsnort, and Ethereal.
Once you're done working in Knoppix, shutdown is handled nicely. As the system shuts down, the CD tray opens, and an onscreen reminder prompts you to remove the disk. Features like this have rightfully earned Knoppix a reputation for ease of use.