Possibly a nutty idea, but: Has anyone ever tried installing RHL as usual and then swapping out the Red Hat kernel for a User Mode Linux kernel and running one copy of RHL "on top of" another, separate Linux installation? Did it boot? - after some fiddling of course! How fast? Could you connect to the host X server and run KDE? Issues that required configuration changes? I don't want to use a "prebuilt" image from the UML site, I want to use the official RHL ISOs, so that I can set up the guest system how I want it (and learn whatever's necessary to set up UML "by hand" in the process). I'd like to run an "almost-pristine" copy of RHL (current beta/release version, and previous release version, which right now would be RH9) "on top of" my main system (which is a mishmash of packages from various RPM repositories). I think UML has something like a copy-on-write feature which allows you to keep the guest system pristine (like VMWare can). This would be a godsend for: reproducing and filing bugs (rather than having to annoy people by saying "Um, I've got a funny kind of mix of packages from RH7,8,9, Rawhide and Severn here, with some extra custom packages", I could say "This is the output on a freshly-installed RHL system" - which makes the bug less likely to be caused by a system configuration error); and for building RPMs for distribution (making absolutely sure that the build is against a pristine system, so no non-standard packages are there to screw up the build). UML is also, of course, damn useful for trying out experimental or in-development kernel patches/modules/kernels which might cause kernel crashes or trash data, as long as they don't need direct hardware access. Things like enbd, kernel hooks for userland filesystems, etc. All without having to reboot and without having to waste resources on a second physical machine. I used to use VMWare for trying and using out different distros, but this is obviously closed-source and expensive. Also, from an engineering point of view UML is a much cleaner approach than VMWare's, for a variety of reasons. Of course, the fact that the kernel is UML rather than the RedHat kernel could be a source of differences, and UML can't do everything that a real kernel can do (yet) but I still think it would be valuable. If there are a lot of configuration issues, perhaps a package could be produced that sets up sensible defaults. OR EVEN - ambitious project here - hack anaconda so that an ISO could somehow boot (with a little helper script and an on-ISO UML image) AND install itself, all within UML! That would be a fantastic hack! And it would be something to set Red Hat apart from other distros (for about 1 version ;) [*] -- Robin [*] Actually, I've just found out that RH8 had a UML _kernel_ included, but this was dropped in RH9 due to patching issues, but it will be back because it's in kernel 2.6 - see: "Red Hat Linux 9 Technical Changes - or when the RELEASE-NOTES are just not enough" http://www.gurulabs.com/RedHatLinux9-review.html
