Knoppix: Linux on a CD


This article was published by ComputorEdge, issue #2113, 2003-03-28, as a feature article, in both their print edition and their website.

What keeps Microsoft executives awake at night? The possibility of millions of PC users discovering an alternative to Windows — especially one not requiring the purchase of a Mac. When those suits finally drift off to fitful sleep (while counting dancing paper clips), their nightmares may be filled with images of… a smiling penguin. That would be Tux, the mascot of the hottest operating system in the desktop world, Linux (or, more correctly, GNU/Linux). This free and open source OS combines the power and stability of Unix with the cost-effectiveness of PC hardware.

Many PC users are eager to sample Linux, but are understandably hesitant. They may lack the time or an available partition to devote to a Linux installation — all simply in order to try a different operating system. If only they could run a flavor ("distribution" or "distro") of Linux that does not require any changes whatsoever to their hard disks. Well, now they can, with Knoppix, a complete package of GNU/Linux software, device drivers, utilities, and other applications. It all fits on a bootable CD, in compressed format, with components being uncompressed and run in memory as needed. Moreover, it supports the most common PC hardware, automatically detecting and configuring it during boot up.

Yet despite its compact format, Knoppix is loaded with applications: Version 3.1 sports seven development tools and languages (including Perl and Python), 14 text editors (including Emacs), powerful graphics programs, Web browsers (including Mozilla, which can nuke annoying pop-up ads), music players and mixers, 77 games (including Tetris and billiards), and several productivity suites (with word processors, spreadsheet programs, etc.), including Open Office. It even includes WINE, a Windows emulator for those rare occasions when you miss your Windows applications…

Given that the operating system components must be read from a CD on-the-fly, it might be expected that Knoppix would take considerably longer than Windows to boot up. However, it requires only about 15 more seconds than Windows 2000 to do a full startup. Once loaded and running in memory, Knoppix and its applications are just as responsive as Windows and its comparable applications. For even faster performance, you can install it on a hard disk, which of course has the additional benefit of avoiding having to boot from a CD at startup.

Linux to Go

Knoppix was originally conceived as an educational project by its inventor, Klaus Knopper, and has now blossomed as more people discover the potential uses of a portable Linux distro on a CD. For instance, you may wish to demo your software on a client's PC without affecting their hard disk, or utilize a familiar environment on a borrowed PC, or learn Unix commands at a command prompt, or demonstrate the features of Linux to your skeptical co-workers. For Linux evangelists eager to spread the word, Knoppix is a godsend. Finally, if you have an old PC missing a hard disk drive, you could still use it as a diskless workstation, for accessing the Internet, playing music, etc.

If a full-blown operating system shoehorned onto a CD is still not small enough for you, you could always try one of the "tiny" versions of Linux now available, each of which can fit onto a single 3.5-inch diskette! But that's another story.

Don't Go Changin'

There are obvious advantages and disadvantages to using an operating system on a read-only CD. The primary benefit is that it allows you to try this increasingly popular OS without running the risks involved with modifying your hard disk. In that case, Knoppix is the safest and most convenient version of Linux that you can try. If for whatever reason you are not happy with it, or you would like to switch back to running Windows at the moment, then simply pop out the CD and reboot your system.

At first glance, being able to run a complete operating system on a machine that does not have a working hard disk drive, might not appear to be of much value. But it actually could be a lifesaver if and when your hard disk drive dies (the ultimate reminder to do backups…) and you need to boot to a fully functional system in order to examine that drive and hopefully bring it back from the dead — or at least recover as many files as possible. An alarmingly large proportion of computer users do not have bootable diskettes that support the formatting schemes of their hard disks' partitions (for file recovery) — especially bootable diskettes containing drivers that support their current CD drive (so they can run recovery programs from CD). Also, booting from diskette will be a less viable solution in the future as more PC manufacturers push to no longer include diskette drives in new systems.

A possible problem of a read-only OS, is that its many components cannot easily be customized for the individual user. Knoppix partially obviates this issue by allowing critical user settings to be saved onto a single diskette, which can be read the next time Knoppix is started. In addition, from the perspective of spyware and other threats to privacy, it can be advantageous that applications as well as the underlying operating system are unable to store your personal information. Not long ago, some of Knopper's fellow techies in Germany deciphered the data that is sent to Microsoft when you perform a Windows Update — it turns out to contain detailed information about all of the software installed on your computer, even that which has nothing to do with Microsoft.

Just Try It

If Knoppix sounds intriguing, you are encouraged to take this Linux-on-a-CD for a spin. Simply download the ISO image of Knoppix from its primary website and burn it to a CD. Or, if you don't have access to a CD burner or broadband connection to the Internet, you could always order a CD at nominal cost, from one of the many companies listed on that website.

Perhaps the best resource for technical information is, which has online documentation, an FAQ, discussion forums, etc. LinuxTag hosts several discussion groups. These websites also explain how to access Windows disks, set the root password, save your configuration to diskette, etc. Even though there are no Usenet newsgroups dedicated to Knoppix, you can post your questions in one of the Linux newsgroups, with a fair chance of receiving a response.

The Incredible Shrinking OS

As countless industry pundits have observed, the various renditions of MS Windows — as well as their most common applications — are becoming increasingly bloated. That portly OS now consumes over 1.5 GB of your hard disk, not counting the built-in advertising for various unwanted services. This kind of binary cellulite compels PC users to purchase ever larger hard disks, and to wait even longer for the OS to boot off those disks.

Fortunately, we are free to explore the alternatives. When you experience all that Knoppix has to offer, conveniently packaged onto a single CD, you will know why Tux is smiling.

Copyright © 2003 Michael J. Ross. All rights reserved.

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