< Back to index

Knoppix, also spelled as KNOPPIX, is a computer operating system which can be used as a live CD. It is a Debian based Linux distribution, developed by Linux consultant Klaus Knopper.

When repairing systems with non-booting hard drives, live CD operating systems like Knoppix are a much more comfortable environment than the previous solution of boot floppies, thanks to the complete graphical environment and networking.

Although Knoppix is primarily designed to be used as a live CD, it can also be installed on a hard disk like a typical operating system. Computers that support booting from USB devices can load Knoppix from USB flash drives and memory cards.

There are two main editions of Knoppix: the traditional Compact Disc (700 megabytes) edition and the DVD (4.7 gigabytes) "Maxi" edition. Each of these main editions have two language-specific editions. One language is English and the other is German.

When starting a program it is loaded from the optical disc and decompressed into a RAM drive. The decompression is transparent and on-the-fly.

Knoppix mostly consists of free software, but also includes proprietary software.

Usage



There are several possible uses of the Knoppix live CD:
* an introduction to Linux, especially as a desktop operating system
* in-store testing to determine whether a computer system is compatible with Linux before purchase
* providing a safe Web browsing environment that is less susceptible to viruses, privacy invasion and data loss
* restoring a system with a corrupted operating system or some of its data
* bootstrapping an operating system installation
* forensic investigation on hard drives

Contents


More than 1000 software packages are included on the CD edition and more than 2600 are included on the DVD edition. Up to 9 gigabytes can be stored on the DVD in compressed form.
These packages include:

* Part of KDE, the default desktop environment; includes the Konqueror web browser and the Kmail e-mail client. Knoppix is also packaged with several other window managers, including Fluxbox.
* XMMS, with MPEG video, MP3 audio, and Ogg Vorbis audio playback support
* Internet access software, including the KPPP dialer, ISDN utilities and WLAN
* The Mozilla Firefox web browser
* K3b, for CD (and DVD) authoring and backup
* The GIMP, an image-manipulation program
* Tools for data rescue and system repair
* Network analysis and administration tools
* OpenOffice.org, a comprehensive office suite
* Many programming and development tools

Requirements


There are some requirements for a computer to be able to run Knoppix, which include:
* A CD-ROM drive
* To start KDE, as happens by default, about 96 MB of RAM is required.

Saving changes in the environment


Prior to Knoppix 3.8.2, any documents or settings a user created would disappear upon reboot. This lack of permanence made it necessary to save documents explicitly to a hard drive partition, over the network, or to some removable medium, such as a USB thumbdrive.

It was also possible to set up a "persistent home directory", wherein any documents or settings written to the user's home directory would automatically be redirected to a hard drive or removable medium, which could be automatically mounted on bootup. What is stored there physically is a file called knoppix.img. The file is used to simulate a file system into which files are written for later use. This is transparent for the user. What the user perceives is that it is possible to write files to the home directory.

Since Knoppix 3.8.1, a UnionFS filesystem transparently saves any new or changed files to a writable filesystem - one which can reside either in memory (ramdisk) or on a hard disk, USB thumbdrive, etc.

This means that the user can modify the software installed on the Knoppix system, such as by using APT to install or update software.

By carrying a Knoppix CD and a USB thumbdrive, a user can have the same environment, programs, settings, and data available on any computer.

Boot options


When using Knoppix as a live CD, boot options, also known as 'cheatcodes', can be used to override a default setting or automatic hardware detection when it fails. For example, the user may wish to boot into a plain console, or proceed without SCSI support. For this, Knoppix allows the user to enter one or more cheat codes at the prompt before booting. If the user doesn't enter a cheat code, or if no key is pressed before the timeout, Knoppix will boot with its default options. For example, to set the language to French rather than the default, one would type:

knoppix lang=fr

Popularity


Knoppix is reported to be one of the most popular LiveCD Linux distributions.