If you've ever needed a functional Linux setup that is portable and runs the same way on any hardware, read on. Knoppix packages a specialized and highly useful Linux distribution on a single, bootable CD-ROM.
Computers should work for humans, but too often the relationship has been upside down. Technologies such as Knoppix and Live Eval, though, illustrate a way in which Linux radically alters computing's "terms of trade."

Knoppix offers advantages for common situations you're likely to encounter. Let's start with a look at a few concrete applications of Knoppix and related packages that you might need in your own computing.

Knoppix boots Linux

Knoppix is a bootable CD. Although it's certainly not unique in that, the organization and content of a Knoppix CD are distinctive. Consider a few scenarios. Suppose you're an instructor. You meet your students in a training room, with only half an hour to check out all the hardware and prepare configurations for them. The result is inevitable: halfway through class, some of your demonstrations won't work, because at least a few of the student machines will have inconsistent Service Pack installations, or hardware that's never been exercised, or an environment customized by a subtle neurotic.

Or perhaps you have piles of commodity hardware. No one particularly cares about all that computing capacity -- except on the few days of the year around the Super Bowl, or Tax Day, or perhaps when your organization runs its quarterly massive simulations of the weather patterns over the North Pacific. How do you bring all those heterogeneous hosts into effective teamwork, without investing too much of your own time in tedious configuration "burn-in"?

Maybe you're just a mobile person; you move around and would happily use whatever desktops are available, but in practice you find they rarely have the software you consider necessary for a minimal working environment. You might want a quick way to set up a security scanner, a well-equipped office automation desktop on a firewalled interior network, or a secure server. Or perhaps you're often called to check out consumer-grade machines with mysterious symptoms. If you could simply exercise a consistent set of diagnostics, you wouldn't have to rely so much on end-user speculation such as, "the modem has a virus, doesn't it?".

These are just a few of the occasions when Knoppix solves simply what otherwise can be thorny problems. Knoppix's inventor, Klaus Knopper, is himself a trainer who launched the Knoppix project, "in between 1999-2000," in his recollection, as an educational project and to meet his own requirements.

As 2003 begins, the main Knoppix product is an open source CD-ROM that boots into GNU/Linux. It is remarkably effective and swift at detecting hardware and installing correct drivers, and it cleverly uses on-the-fly decompression to make room for almost 2 GB of applications and data. Moreover, as Knopper tells it, one of Knoppix's main features is "the GPL license for the software collection as well as all scripts and tools written by me, which allows the recipients to modify, distribute, and sell the CD on their own."

Still, this simple description hides plenty. While Linux adepts often experiment with bootable media, and many applications rely on data compression, Knoppix shows a singular level of polish. It is simple, but only because Knopper and a few other project contributors took so much care in constructing it to be that way.

Knoppix features

Consider these highlights:
Knoppix is swift. Most Knoppix users mention a boot-up time of under two minutes, on unremarkable hardware. One user told me: "You put the CD in, wait a minute or two, and [you] have a KDE with a bunch of apps running." That's Knoppix' target: it boots without user interaction to runlevel 5, launching X and KDE along the way.
Knoppix is comprehensive. It includes an extensive collection of hardware drivers and well-crafted facilities for detecting them, so that common hosts boot with all hardware already operational. Knoppix's knowledge includes not only a wide range of graphics cards and mice, but also sound cards, modems, and USB and SCSI devices. Software, including OpenOffice, security applications, and GIMP, covers a wide range of common needs.
Knoppix is comfortable. It's adapted from widely respected Debian distributions. As a CD-ROM, it's formatted in iso9660 rather than (read-only) ext2, for the maturity of the ISO standard.
Knoppix is adaptable. An early Knoppix variant was a "bootable business card" -- a "rescue" or "survival" Linux system in a minimal form factor.
Knoppix is flexible. It does the right thing in such circumstances as remote booting. Clients without a CD-ROM drive but with a Linux-supported bootable network card, for example, can boot remotely from a Knoppix-running server by means of PXE.
Knoppix is polite. One of the domains where Knopper's craftsmanship shows through is in security. Knoppix comes up treating its host's mass storage as read-only. You can do useful work with Knoppix -- track down a network security problem, prepare and distribute a memorandum, or view a downloaded multimedia presentation -- confident that, once you pull out the CD-ROM, the host system will return to its normal operation.
Knoppix is liberal. Its standard version, along with the software used to construct it, are open sourced. Knopper also customizes Knoppix for those with specific licensing, configuration, or other proprietary needs.

The Resources section later in this article provides several other interesting Knoppix uses. Consultant Rolf Ade told me how Knoppix goes on shopping trips with him: "It's really great to carry a Knoppix CD with you, if you want to buy a new Intel box for running Linux. Just boot it with the Knoppix CD and you will know if there are Linux drivers for all [its] hardware."

Many people favor Knoppix as the best possible Debian installer. Knopper also has plans to allow Knoppix to configure terminal servers.

Starting out with Knoppix

The easiest way to begin your own use of Knoppix is with a vended CD-ROM. Almost a score of distributors in Northern Europe, the United States, and Australia process orders for Knoppix CDs, including betas.

If you have bandwidth to burn, you can download the over 600-MB Knoppix ISO image, available at no charge through the Knoppix download/order page (see Resources). Mirrors are abundant around the world. Remember that you can burn a CD-ROM from any operating system; you don't need Linux to create a Knoppix CD.

With a standard Knoppix CD-ROM in hand, you've almost reached Linuxland. All you need is a capable PC-class machine: 80486 or later, at least 20 MB of RAM (although with anything less than 128 MB, you'll have to give up office products and perhaps the desktop manager or even X11 server), standard SVGA, and a means to boot. Even without these, it's often possible to use Knoppix. Look first, though, at a conventional situation:

If the PC boots from CD-ROM, slide in the Knoppix CD and you should have a recognizable, useful Linux two minutes later. Many BIOSes have the capability to boot from CD-ROM but aren't configured for it. In this case, you might need to restart the PC and enter "BIOS setup" or "BIOS features" by pressing Delete or another hardware-specific key on startup. When you configure the boot medium, remember that it doesn't have to be the CD-ROM exclusively, or even first; it's fine to sequence a floppy drive before the CD-ROM. All you need is to ensure that the CD-ROM is present as a recognized boot source. Save the new configuration, and you should be ready to start.

An alternative is to boot from a floppy disk that recognizes the CD-ROM and passes off boot control to the latter. These are often called "startup diskettes." The Knoppix image includes a "rawrite" program, which prepares such diskettes.

If Knoppix works well for you, it's natural that your next instinct will be to change it. While customization of Knoppix isn't a secret, most effort on the project has gone to making the standard installation "bullet-proof." Among the several distinct ways to alter Knoppix, the one likely to be of broadest interest is remastering, during which you can substitute your own software for a portion of that on the standard Knoppix CD-ROM. Toward the end of 2002, Jubal John prepared an authoritative "How to remaster ..." document, listed in Resources. This process is a rather delicate one, and too involved to abbreviate here. The main difficulty is that low-level management of disk partitions risks system integrity, if anything goes wrong.

Knoppix alternatives

I'm enthusiastic about Knoppix, and I'm far from alone. I've heard from dozens of administrators and network managers with such affection for Knoppix that they "wouldn't leave home without it." Any Linux professional or hobbyist operating in an environment that's at all dynamic -- even just an occasional need to run on others' equipment -- should try out a copy of Knoppix. The cost to do so is vanishingly low, and the potential benefits and convenience are quite high.

Knoppix has also proven friendly to business initiatives. Knopper relates that "there are many Knoppix derivates around; some have been published by the purchasers, and some are used only internally inside a company. It is the customer's decision whether or not to publish the free software product he purchased, since the GPL does not require you to publish or give away a customized version, and does not even force you to include only free software on the same media. So, some companies use Knoppix as a platform for their free, or also proprietary, software, in order to show a demo version of their product to potential customers without the hassle of an installation on hard disk before they can use it."

Be aware, though, that there are specific applications of Knoppix where alternatives might serve you better. The Resources section shows a few of these. If you work much with older equipment, for instance, Knoppix probably isn't practical. Knoppix's standard configuration demands too much memory -- 32 MB isn't enough. That's a case where projects such as muLinux are more likely to help.

Knoppix can also be viewed as a "least common denominator": its purpose is to get the computer running with as little delay or human assistance as possible. Among other consequences, this means that standard Knoppix gives users no chance to configure exotic video or network settings before KDE comes up.

Products like SuSE's Live Eval take a different approach. Live Eval aims to mimic as much of a full SuSE distribution as possible from a single CD-ROM. In particular, it expects user interaction for its boot sequence and configuration. This gives more flexibility, but even an experienced SuSE engineer told me it takes around seven minutes to boot to the point Knoppix typically arrives at in under two. On the other hand, a Live Eval session affords a more accurate glimpse of what it's like to use a full-blown Linux distribution in a standard working environment.

Pascal Scheffers, a programmer with Erasmus University, described still another situation where Knoppix and vendor products provide different solutions. Suppose you need to test the installation of a product. If the tool at hand is Knoppix, you might dedicate one host to installation tests, and perhaps use Ghost (or Ghost-for-Unix) to help automate the installations. Knoppix gives a standard starting point for use of the host.

For this sort of problem, Scheffers likes to use VMware and its "non-persistent" option. VMware can host an operating system within a particular session, exercise an installation, then roll back all changes to their initial state.

Conclusion

Knoppix solves problems -- at least many of the problems I commonly encounter.

Beyond that, I like the way Knoppix puts people back in charge of the computers. Too many users now habitually believe it's proper that preparation of, say, a simple slide presentation, should require expensive and time-consuming upgrades in hardware and software, as well as laborious installations and configurations. When something goes wrong, it's regarded as a mystery that might only be solved by starting from scratch. In any case, people wait while computers operate on their own schedules.

In complete contrast to those sad scenarios, Knoppix exemplifies the virtues of Linux's openness and flexibility. Knoppix manages a wide variety of hardware and quickly brings it to a state that is useful to humans. That's a model that deserves imitation.

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