http://rasteri.blogspot.ca/2011/03/chain-of-fools-upgrading-through-every.ht...
I must stand corrected, as although I knew this was theoretically possible, I didn't believe it could actually be done successfully. -Adam
I started with MS-DOS, installed Windows 3.1, and have upgraded all the way to XP. For each hardware upgrade, I clone the hard drive. It works, that's my computer. Windows ME required some tweeks to make it stable, but I did it. I never did use Windows 2000: MS-DOS -> 3.1 -> 95 -> OSR2 -> 98SE -> ME -> XP.
Rob Dyck
As for a linux-y twist on the story, I've successfully "yum upgraded" at least a dozen production boxes from Fedora (Core) 4 through to Fedora 19 (the current version), without any great deal of trouble when following the readme's. And all of those were remote upgrades with ssh on headless boxes! Try doing headless upgrades with Windows (LOL)! Only 2 or 3 were a pain, like the align-to-2048-sector grub2 change, the /usr/bin->/bin change, etc.
I should mention, the key to successful Fedora upgrades (this may apply to FedUp also) is _do not skip versions_. What I often end up doing is an upgrade to ver X and then immediately (like same day) upgrade to ver X+1. If you want to skip versions, a DVD-based anaconda upgrade is the best path.
So everyone doesn't get the impression, after Gilbert's comment at the meeting, that Fedora sucks, I love Fedora and use nothing but Fedora (nee RH) since 1999 on boxes I control. I've had to administer Ubuntu and SUSE before and always hate trying to figure out their "weird" way of doing things, especially config location and networking setup. (To each his own!) It's also easy to switch to XFCE or whatever without using a "spin". I've switched desktops and WM's quite a few times in 14 years and never do a "wipe/reinstall". Granted, I am quite comfortable with going "under the hood" and would probably no longer be considered a novice.