FMod - Installable OS

It's possible to boot Windows PE from a hard disk, so I thought it might be kind of interesting to add a means of installing AbiatharOS to the hard drive, thereby allowing persistent changes to be made on the system volume, since it would be a hard disk rather than a RAM disk.

It turns out this was fairly easy to do. There's now an "Install" option on the OS menu, and it's hidden if the flag file indicating a persistent install is present. The presence of this flag also causes the configuration disk chooser to allow the use of the X drive. The installation wizard just prompts for the CD drive letter and the letter of the destination drive. (Good guesses fill in both boxes by default.) Once the user hits "Install", Abiathar invokes ImageX to decompress boot.wim onto the hard drive, then does a bunch of stuff with the BCD store to configure booting.

I tested it (in a VM, of course) and it works every time. It doesn't support UEFI configuration, but I don't know of any real machines (in personal use) that don't have BIOS compatibility in their UEFI implementation. I'm still not sure if anyone will want to use, much less install, this, but I'm learning a lot and having fun.