Knoppix


Knoppix, stylized KNOPPIX, is an operating system based on Debian designed to be run directly from a CD or DVD or a USB flash drive. It was first released in 2000 by German Linux consultant Klaus Knopper, and was one of the first popular live distributions. Knoppix is loaded from the removable medium and decompressed into a RAM drive. The decompression is transparent and on-the-fly.
There are two main editions, available in both English and German: the traditional compact-disc edition and the DVD "Maxi" edition.
Knoppix mostly consists of free and open source software, but also includes some proprietary software, as long as it fulfills certain conditions. Knoppix can be used to copy files easily from hard drives with inaccessible operating systems. To quickly and more safely use Linux software, the Live CD can be used instead of installing another OS.

Contents

More than 1000 software packages are included on the CD edition, and more than 2600 packages are included on the DVD edition. Up to nine gigabytes can be stored on the DVD in compressed form. These packages include:
Minimum hardware requirements for Knoppix:
  • Intel/AMD-compatible processor
  • Minimum RAM memory requirements:
  • *32 MB for text mode;
  • *Live environment with no swap:
  • **512MB for graphics mode with just LXDE
  • **1GB to use the web browser and productivity software
  • **2GB recommended
  • Bootable optical drive:
  • * DVD-ROM for current versions;
  • * CD-ROM for version 7.2 and older, or a boot floppy and standard CD-ROM
  • Standard SVGA-compatible graphics card
  • Serial or PS/2 standard mouse, or an IMPS/2-compatible USB-mouse.

    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 persistence then made it necessary to save documents directly to a hard drive partition, over the network, or to some removable media, such as a USB flash drive.
It was also possible to set up a "persistent home directory", where any documents or settings written to the user's home directory would automatically be redirected to a hard drive or removable media, which could be automatically mounted on bootup. A single file, knoppix.img, was cached on the rewritable media and used to simulate a file system into which files were written for later use. This allowed the user to transparently write to their home directory.
Union mount support was added in version 3.8.1 through UnionFS. This was later replaced by Aufs in 5.1.0 to improve stability. The union mount allowed virtual updates to the data on the read-only CD/DVD media by storing changes on separate writable media and then representing the combination of the two as single storage device. The writable media could be memory, a hard disk, USB flash drive, etc. This means that the user could modify the software installed on the Knoppix system, such as by using APT to install or update software. The storage device containing the changes needed to be present whenever Knoppix is started, else only the original data from the disc would be used. While Knoppix would scan available storage devices for a persistent home directory by default, a user could dictate a specific location with a boot option such as:
home=/dev/hda1/knoppix.img
By carrying a Knoppix CD and a USB flash drive, a user could have the same environment, programs, settings, and data available on any computer that could run Knoppix.
This functionality was only available through Knoppix 5.1.1 or 5.3.1. Subsequently, the Live CD paradigm has transformed into portable operating systems that run on external storage.

Boot options

When using Knoppix as a Live CD, one can use boot options, also known as "cheatcodes", 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 does not enter a cheat code, or does not press any key 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
Knoppix is a 32-bit Debian Linux based distro, but recent releases have also been equipped with a 64-bit kernel on the DVD edition, where it will automatically boot up for 64-bit computers, or by using the boot option knoppix64 manually in the command-line prompt, while knoppix will boot up the 32-bit kernel. Neither PAE nor 64-bit applications are supported by Knoppix, and more than 4GB of system memory can only be used with a 64-bit kernel.
The DVD edition of Knoppix can also be loaded onto a USB flash drive, with flash-knoppix under the Knoppix system, such that "the KNOPPIX Live System starts and runs about factor 5 faster from USB flash disk than from CD or DVD!". Besides that, the experimental UEFI support is provided for USB flash drive rather than DVD media. 32-bit UEFI firmware can only boot up the 32-bit kernel, while 64-bit UEFI firmware can only boot up the 64-bit kernel. The text interface for UEFI is similar with it for BIOS, one can also press key F2 and F3 to access information on boot options.

Popularity

Knoppix was one of the first Live CD Linux distributions to gain popularity. There are several factors that contribute to the popularity of Knoppix:
  • Knoppix was one of the first Live CDs available, and is known as the "original" Debian-based Live CD
  • Its extensive hardware detection allows most systems to start Knoppix without any configuration
  • Its ability to automatically connect to most kinds of networks
  • Its utilities for system repair and troubleshooting
Knoppix works on a fairly large number of PCs or laptops, but not all. The automatic hardware detection cannot cope with all hardware, and sometimes the drivers used will not be optimal. Knoppix has difficulty recognizing some cards made before 1998, or motherboards with a BIOS made before 2002.
If a PC does not have enough RAM to run KDE and other included programs, the legacy Knoppix boots up a very limited Tab Window Manager session instead. The only window running in the twm session by default is xterm.

Versions

VersionRelease dateCDDVD
1.42000-09-30
1.62001-04-26
2.12002-03-14
2.22002-05-14
3.12002-10-01
3.22003-06-16
3.32003-09-22
3.42004-05-17
3.5 LinuxTag version2004-06
3.62004-08-16
3.72004-12-09
3.8 CeBIT version2005-02-28
3.8.12005-04-08
3.8.22005-05-12
3.92005-06-01
4.0 LinuxTag version2005-06-22
4.0 updated2005-08-16
4.0.22005-09-23
5.0 CeBIT version2006-02-25
5.0.12006-06-02
5.1.02006-12-30
5.1.12007-01-04
5.2 CeBIT version2007-03
5.3 CeBIT version2008-02-12
5.3.12008-03-26
ADRIANE---
6.0.02009-01-28
6.0.12009-02-08
6.1 CeBIT version2009-02-25
6.2 / ADRIANE 1.22009-11-18
6.2.12010-01-31
6.3 CeBIT version2010-03-02
6.4.32010-12-20
6.4.42011-02-01
6.5 CeBIT version2011-03
6.7.02011-08-03
6.7.12011-09-16
7.0.12012-05-24
7.0.22012-05-30
7.0.32012-07-01
7.0.42012-08-20
7.0.52012-12-21
7.2.02013-06-24
7.4.02014-08-07
7.4.12014-09-15
7.4.22014-09-28
7.5 CeBIT version2015-03-16
7.6.02015-11-21
7.6.12016-01-16
7.7.0 CeBIT version2016-03-14
7.7.12016-10-27
8.0.0 CeBIT version2017-03-24
8.1.02017-09-27
8.2.02018-05-16
8.3.0 2018-06-07
8.5.0 Linux-Magazin / Linux-User edition2019-03-14
8.6.02019-08-08
8.6.12019-11-22
9.0 2020-03-05
9.12021-01-25
9.2 2021-04
9.3 2022-06

The table shows the version history of major releases.