--- Matthew Miller <mattdm@xxxxxxxxxx> wrote: > So, tell me -- is this a crazy idea? Certainly no crazier than this idea I mentioned on the livecd list- --------------------------------------------- Rebootless Installer - Implementation Outline --------------------------------------------- Goal: A cd/dvd/bluray iso which serves as both a traditional livecd, and a traditional install cd (functionally akin to current ubuntu stuffs, but radically different implementation, as well as 'rebootless' feature) 1) take your linux distro (i.e. fc6). Create a "hardware agnostic" minimal (but useful) installation. I.e. resulting install image can be booted on any supported hardware, and all hardware configuration is done during normal system boot. I.e. the type of system installation you would put on a traditional 'livecd'. Now put this on a livecd, but with a cutting edge boot method such as... 2) the latest linux-from-scratch livecd implements a particularly novel livecd system. Traditionally, various implementations have usually used ram based tmpfs, combined with rom based cd/dvd iso9660, zisofs, squashfs. Along with some bindmounting, or unionfs to get a nice copy-on-write action going. The latest LFS livecd however uses a radical method of storing the system as an ext3 filesystem image (sparse file) on the cd/dvd iso9660 fs, but compressed with zisofs. Then, during early boot, a tmpfs is created, and a large sparse file is created in tmpfs. This sparse file in tmpfs is then used as a devicemapper snapshot device, allowing an alternate COW mechanism to the traditional unionfs mechanism. Now, extending the radicalism- 3) make the following change to (2): Instead of using the sparse file image on dvd, and in tmpfs, use device mapper mirrors for both, initially created as broken mirrors, with the unbroken half being the same image used in (2). 4) now, one can implement an installer application on the livecd like so: - have user create target partitions the traditional way - now, to install, just set the target partitions as the unbroken halfs of the device mapper mirrors created in (3). Then let the device mapper "install" the system by repairing the mirror. - once the mirror is unbroken, manually rebreak it, the opposite way, so the tmpfs image, and cd/dvd rom can be discarded/forgotten-about/unmounted/ejected. - thus once the installer has completed, the same livecd system that the user has been looking at and playing with, _*has become the installed system*_. No reboot is necessary, except for normal kernel maintenance as released updates dictate. - one beneficial side effect, is that the system will be prepared from the beginning for the user to optionally add another disk to be used to 'fix' the broken mirror. (or alternately the bootscripts could remove the broken mirror cruft during the next reboot, so it looks like a perfectly 'normal' system). - one last note, I haven't actually experimented with all of this, but I'm guessing that it's also possible to make the COW dm-snapshot device disappear by "writing back" it's contents to the main image. Otherwise one would have to keep around the original small system image (which isn't necessarily a useless side effect). -jdog __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
