"The software distribution system that works differently.
rootz mounts complete live distros over the web, and make them available locally.
Attach your local linux system to various mirrors and simply
run applications, without any installation or prior downloads!

* No special repackaging is needed (as opposed to klik, zero install or autopackage).
* True "on demand" mechanism that does not require full download of the software but fetches only the needed files.
* Support multiple mixed images - run experimental apps from debian sid side by side with ubuntu stable app, fedora, mepis and more.
* Secured - unchanged, isolated (chrooted) images."

http://vamosproject.org/rootz

I'm proud to announce rootz, a tool that runs applications from web-hosted live distros.
With rootz users can run live software without installing anything to their computer.
rootz is connected to the desired image (iso or squashfs), and any click on rootz:// link will launch the application.

The main advantage of this system, is that it uses unchanged official software without any repackaging (as opposed to klik, zero install or autopackage). Moreover, it is a true "on demand" mechanism that does not require full download of the software but fetches only the needed files. rootz can set up a multiple isolated chroot environments, so it is possible run stable application side by side with bleeding edge software.

Currently only Debian based system livecds are supported - Debian Live, *Ubunutu, Mepis, etc. Support for more software and other features are planned on Vamos which is the project behind rootz.

QEMU-Puppy is an OS and a set of applications on a USB memory stick. This OS can be booted natively, or on top of an other, already installed, OS. Just borrow a PC, boot your own environment and return the PC unaffected. [...]

A bootable USB memory stick has some disadvantages as well. First of all, not every PC is able to boot from USB. Second, if the machine does boot from USB, not all hardware is detected or configured properly, since the hardware "changes" every day. Third, booting from USB "locks" the machine: It's either the natively installed OS or your OS, not both at the same time.

To get rid of these disadvantages, you can carry your own machine as well, not only your files, your applications and your OS. You can do this by buying a laptop. But it's expensive, a physical burden and risky. The USB memory stick is cheap, light and easier to protect. A virtual machine, like QEMU, is cheap, light and easy to protect as well. With such a virtual machine, we are able to boot our OS on top of the natively installed OS. Now we have two OS's running concurrently on one machine! ALT-TAB is enough to hide your machine and get back to work...

The tricky part is trying to have the OS on your USB memory stick to be able to boot natively, as well as in a virtual machine. But it can be done. And that's what this document is all about..."

http://www.erikveen.dds.nl/qemupuppy/index.html

http://www.erikveen.dds.nl/qemupuppy/qemu-puppy.tar.gz