How To Love Linux On The Desktop

Blowing away a computer and installing a different operating system is all part of a day's work for the Test Center. In fact, some projects in the Test Center over the past year have included a lot of time spent simply installing and reinstalling various Linux distributions on a single machine.

Test Center staff have found a number of good reasons for removing a Linux distro entirely and doing a clean install. For testing and evaluation purposes, however, it's helpful to have multiple systems available simultaneously for comparison. This is where virtual machines really come in handy.

VMware Corp., Palo Alto, Calif., has dominated headlines with its VMware Server, but there are plenty of other vendors with various flavors of VM software, including Microsoft's HyperVisor.

Be Patient
Creating virtual machines on a Linux host system can be frustrating. Installing VMware Server on a Linux box to run multiple Linux distributions was difficult enough that it was preferable to install VMware on a Windows machine and run multiple Linux virtual machines instead. For this system builder recipe, virtual machines were created in Linux using open-source QEMU, a free application from French computer programmer Fabrice Bellard.

A command-line application, QEMU, is a fast processor emulator and virtualizer. Currently, the package supports ARM, PowerPC, SPARC and x86 emulation. While we missed the easy point-and-click interface that comes with Windows packages, creating virtual machines was a less aggravating process. Using QEMU, virtual machines for Fedora, CentOS, Gentoo, Mandriva and PuppyLinux were created on top of the Ubuntu host.

While many modern Linux distributions have QEMU preinstalled, Ubuntu did not. It was simple enough to download and install using Ubuntu's package manager; the latest source is also always available from fabrice.bellard.free.fr.

Emulation and virtualization are, at heart, two different things. An emulator pretends to be a different machine or to have a different hardware configuration from the host. Fabrice's Web site lists all the processors that QEMU can emulate, as well as prebuilt images of various operating systems available for download. However, performance is not all that great.

Virtualization, on the other hand, actually executes code on the system processor instead of mimicking the processor. As a result, the virtualizer has better performance than the emulator. QEMU offers software virtualization, not hardware virtualization.

On this Ubuntu host, QEMU was located in /usr/bin. Here are five tips to help you get from A to B:

Next: Tip 1: Creating The Virtual Machine