Live CDs Part II: Desktop Replacements

[Editor's note: this is the second in a four-part series; the next installment will appear in the next week or two.]

If you read Part I of this series, you know all about what a live CD is and why you would want one for your own. This week, it's time to look at examples of live CDs that implement complete replacements for your desktop. Remember that the goal isn't to compare these examples but rather to help you learn to differentiate the options available. The ratings for each review are intended to show how well each option might fit a particular need rather than comparing the CDs against one another.

A number of live CD's offer complete desktop environments based on existing desktop distributions or on hybrid or home grown distributions. I chose three live CDs for this category: KNOPPIX as a representative of the hybrid desktop replacement category, the GNOME live CD to see what new features I might find in upcoming desktop distributions and Berry Linux, for a taste of a language customized version.

Desktop live CDs use "cheatcodes", or command line options to the kernel to deal with special situations. Be sure to check out the web sites for information on how to make best use of these.

KNOPPIX

KNOPPIX may be the grandfather of all live CDs, or at least a distant relative. Developed originally by Klaus Knopper, this highly popular and very complete distribution packs in 2GB worth of data into an ordinary 700MB CD. The shear weight of applications should make this distribution bog down on the low memory test system, but it doesn't. Still, the Debian based distribution manages to use up 214MB of an available 229MB running just the KDE desktop.

Unlike more modern live CDs, KNOPPIX appears to use the cloop driver to use compressed filesystem images from the CD. The alternative would be to use the SquashFS filesystem or other compressed filesystem image drivers. Despite using an older driver, KNOPPIX doesn't appear to be suffering performance issues and certainly isn't hobbled by lack of space on the CD.

The CD was slow to boot but correctly identified the hardware except for the mouse. KNOPPIX configured a generic PS/2 wheel mouse while the test system had a simple 2 button mouse without a wheel. The system boots directly into an X session for the "knoppix" user (not root). While a relatively recent 2.6.12 kernel is used, KNOPPIX is using XFree86 4.3 instead of the newer X.org releases and defaults to the VESA X driver. The display does come up in 1024x768 @ 24bit color depth, which makes best use of the test system hardware.

The desktop runs KDE 3.4.1, which runs surprisingly fast on the test hardware. This is probably due to the way KNOPPIX leaves many read-only files on the CD instead of pushing them into the ramdisks. The menu systems is a bit cluttered, however. There are multiple menu entries for doing configuration tasks, for example. And there are to many entries in the main menu, making the menu a bit overwhelming to a newbie.

Applications abound with this live CD. Office files are handled with OpenOffice, KDE PIM tools and Scribus. Xmms and Xine highlight the multimedia support. Along with the usual KDE tools like KMail and Konqueror, network applications include Firefox, Thunderbird, XChat and GAIM. Add to this a large number of graphics and game applications along with plenty of variety in text editors and you've got a full featured desktop.

As with most desktop replacement live CDs, KNOPPIX comes with it's own cheatcodes, which are actually just a bunch of kernel options that you can use at boot time to deal with old or unusual hardware.

Extending KNOPPIX requires copying the contents of the CD to a local directory, then doing a chroot into that directory. From here you can use "apt" to update packages and add your own packages just as you would on any running Debian system. After updates are complete, you remake the compressed filesystem image used by the cloop driver and then remake the ISO image. The runtime system can also be updated using the KPackage utility found under the Utilities menu.

Cleanliness:	7
Originality:	7
On Target:	9
Extensibility:	8

The GNOME Live CD

The GNOME Live CD isn't really a desktop replacement system but more of a technology preview. The CD uses the popular Ubuntu distribution as a base Linux operating system and adds all the bells and whistles of the latest (in this case, version 2.12) GNOME desktop release. While it isn't intended to function like a KNOPPIX distribution, it does contain everything you might need on a desktop.

When the Ubuntu distribution boots you'll get a GNOME splash screen. For some reason I had to hit ENTER at this point otherwise the boot wouldn't continue (this happens on the official Ubuntu live CD as well). The boot takes a long time to do it's hardware detection, partially using text based screens and partially using Bootsplash screens. Eventually, the system boots directly into the "ubuntu" user's desktop.

Hardware detection by the Ubuntu distribution correctly recognized the Via CastleRock graphics support on the EPIA M10000 test system and the CD loaded the "via" X driver. This is different than most of the other live CDs I've tested which default to using the generic VESA driver. It is nice to have the "via" driver for video playing but other than that using the basic VESA driver works just as well on this hardware.

As with KNOPPIX, this GNOME desktop system is heavy on memory use, using 219MB out of 224MB available according to "top". This is expected behavior for this class of live CDs so be certain to have plenty of memory.

Applications include OpenOffice for office documents, Evolution and Firefox for email and the web, the Totem movie player and Rhythmbox music player for multimedia files. The desktop also includes GNOME Meeting, an H.232 compliant VoIP and telephone application that should work with NetMeeting.

Overall the desktop appearance is cleaner than KNOPPIX's. This is probably because KNOPPIX tries to provide every application it can while GNOME is demonstrating GNOME specific features. Again, I'm not trying to compare the two against each other, but rather pointing out how similar live CDs can target different problem spaces.

The GNOME live CD isn't meant as a general purpose solution and as such does not provide tools or methods for extending the ISO image. The desktop does provide the Synaptic package manager which allowed me to install a 3D chess application with ease.

Cleanliness:	8
Originality:	6
On Target:	9
Extensibility:	4

Berry Linux

This relative newcomer to the live CD scene offers a polished desktop environment. Originally designed as a Japanese language live CD based on Fedora Core 5 and KDE, Berry Linux now includes an English language version and a GRUB based boot that offers multiple configurations. This includes an Xgl (an OpenGL X server) version, Safe and Expert boot modes, and support for Vaio and Dynabook specific hardware.

The English boot mode was fast through the hardware detection phase. Berry Linux makes use of KNOPPIX's "hwsetup" to configure hardware and it was successful in finding the VIA graphics hardware and configuring the X environment to use it. Unfortunately, it also configured a generic PS/2 wheel mouse, while the test system didn't have a wheel.

Berry uses a modern 2.6 kernel and the Overlay Filesystem (translucency.o module) mixed with SquashFS and UnionFS for it's CD technology.

Like most desktop replacement live CDs, this system doesn't boot into a root user but rather boots directly into the "berry" user. The root password is "root" (which you'll need for basic system management tasks) but you'll only know this if you read the web site.

While hardware detection is fast, getting into the desktop is a bit slow. A very customized KDE offers up a clean desktop with lots of icons that include a small penguin image.

Applications are abundant here, as you'd expect with this class of live CD. Media files are accessed with XMMS, MPlayer and Xine while office documents can be managed with OpenOffice. Thunderbird and Sylpheed provide email access while Firefox handles web browsing chores. As an added bonus, WINE is provided for support of Windows executables.

Berry Linux is a full featured desktop, but a slimmed down version is also available that uses FluxBox as the desktop environment in place of KDE.

Information on remastering the ISO is available but limited. No information on the format used for packages (RPMs or .deb files, for example) is provided, though a web page on the differences between Berry and KNOPPIX says RPMs were used.

Cleanliness:	8
Originality:	7
On Target:	9
Extensibility:	4

In the next installment of this series I'll look at Small Footprint live CDs. These are the systems that should serve as the basis for embedded systems or for making use of older or less well supported hardware by making it easy to extend the feature set of the CD. Those live CDs under review will include Olive, Puppy Linux and Damn Small Linux.

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