January 27, 2005
Virtual Linux projects Colinux, QEMU, XEN & UML
Several new innovative and interesting linux projects are progressing
Colinux is a project where you can run linux right in windows without the help of virtual pc or vmware. Very cool- but it needs work to make it easier to install.
Looking for a project? Take Damn Small Linux (a debian based 50 meg distro) and make an easy to use installation script for Colinux/QEMU. Actually looks like someone has done it for knoppix. But get the networking work work more simply. Hmm - I've got some ideas...
QEMU seems to be very cool. Seems fairly easy to get going. I downloaded a zip and it ran right away. A lot of people are using it to run windows 98 in linux or Linux in windows. Only two caveats - you need to configure a disk before you install and the resolution you will get on older video cards is limited. Like most emulation software you probably need a fairly quick machine. I've got a windows machine that uses Microsoft Virtual PC to run linux - perhaps I'll switch to QEMU.
UserMode Linux
User-Mode Linux (UML) is a safe, secure way of running different Linux versions and Linux processes. ISPs use this to allow multiple people to have root access to a server. UML implements its virtualization within the kernel rather than at the hardware layer. This is very efficient since there is not a layer of virtual hardware between processes and the physical machine.
Good overview from redhat:
http://www.redhat.com/magazine/001nov04/features/usermode/
More efficient than UML is the Vserver project
Essentially, every virtual vserver shares the same kernel as the host system, although they are all full isolated and protected form each other. This means it's no use for testing new kernels (which is on of the main aims of User-Mode linux), but is more efficient for production servers that most of us run.
Xen
Xen is an open source hypervisor for intel hardware. A hypervisor allows multiple operating systems to run side-by-side simultanously, similar to partitioning on a mainframe. It requires a modified version of the operating system kernel (currently Linux 2.4, 2.6 & NetBSD) and thus is extremely fast.
An Overview from Linux Mag
IBM has released its 710 Server which will eventually allow you to dynamically reallocate cpus and network cards between instances of Linux running. Similar to the stuff Vserver and UML offer but at a hardware level (and running on nice 64 bit hardware).
Colinux
