Run Linux off a CD

This is not just another Linux distro. It’s one of the better things that happened to Linux. Knoppix is a Debian Linux-based distribution that doesn’t need to be installed on a machine to work.You can just boot off its CD and what you get is a fully-functional Linux desktop. Rapid Desktop Deployment (RDD) doesn’t get better than this. The concept of a complete OS on a single bootable CD is not new. DemoLinux and SUSE’s Live-Eval are some examples of where it has already been implemented. However, Knoppix scores over them in terms of its excellent hardware detection and completeness.

Perhaps the most painful part of setting up a Knoppix system is getting the distribution, especially if you have a slow Net connect. For this, you can place a mail order on their official site www.knopper. net. But if you do have enough bandwidth, then go ahead and download the complete ISO image, which is a little over 650 MB, and burn it on a CD. Change your computer’s BIOS setting to boot off the CD and you’re ready to roll. People with older motherboards that don’t support CD booting can rawrite the kernel image (/Knoppix/boot.img) to a floppy disk and use that to boot while keeping the CD in the drive.

There are no login screens even for the text mode when you boot Knoppix. It automatically detects all your hardware, and automatically selects the appropriate screen resolution without human intervention except in rare cases where it asks for the screen resolution mode at the beginning of booting. Once it detects all hardware, it takes you straight to the KDE 3.0 desktop. 

The hardware detection program hwsetup is based on RedHat’s kudzu libraries. It detects, configures and generates the required links for the peripherals. The cloop module is used for decompressing the applications. This and other Knoppix specific software (the kernel) are available for download at their official site, www.knopper.net/knoppix/index-en.html. ISO images are also available for download for easy distribution. However, due to some license restrictions on some of the free applications included, re-distribution is not possible.

This distribution is a perfect stepping-stone for newbies, who may otherwise find it difficult to install Linux (which includes various issues with partitioning and lilo configuration). Moreover, it can be used for educational purposes, and even troubleshooting (as a full-fledged rescue system). The CD has over 2 Gigs of applications stored. These are uncompressed on the fly when executed. 

The completeness of the system can be judged by the fact that it features Kdevelop 1.0 and tons of programming languages–the ones you will find in any typical desktop Linux distribution. The applications are desktop oriented, such as an office suite (Openoffice.org), multimedia applications (KDE applications). Using it is like using any other Linux distro. If you load it on a machine that’s on a network, then it automatically configures itself from a nearby DHCP server. 

Knoppix also has its share of cons, too, which can be expected. Being an OS that runs off a CD, you obviously can’t install any applications on it. So if you want to use it for giving demonstrations of your own applications, it can’t be done unless you add it to the ISO image and then burn it on a CD. This, however, is expected to be rectified in the future releases with plans to add an overlay file system. This will allow users to install software on the ramdisk “over” the read only CD. 

Knoppix is only available on Intel platform, and the minimum requirements for running it are 16 MB RAM, and an Intel 486 or higher. Of course, in order to use it properly, you need a much better system configuration than this. We tested it on a 500 MHz Celeron system with 128 MB of RAM and it worked fine, though some applications took pretty long to load. So, to get the best performance, use at least a PIII-based system. 

Though Knoppix boots off a CD, it allows you to access your other drives such as the hard disk, CD-drive and floppy. By default all Windows and Linux (if any) partitions on the hard disk are mounted automatically in read-only mode, so you must change the mode in order to save data on them. You can, of course, store files in the ramdisk temporarily.

Those with some expertise of Linux may also try to convert the Knoppix CD distribution into a hard disk bootable installation. Check out www.freenet.org.nz/misc/ knoppix-install.html for details. You can also remote boot Knoppix via PXE from a server already running Knoppix. This is useful for computers without a CD-drive.

Ankit Khare