Since Ingo and I started working on CD booting at BeGeistert, we have (or rather, he has) written a TAR file system for the boot loader.
When your IBM compatible computer boots, the BIOS emulates a boot floppy for a CD-ROM instead of giving you access to the disk directly. In order to access the whole disk, we need a CD-ROM driver - and therefore, we also need the kernel to execute the driver.
Be’s and our solution writes the kernel and all modules needed for booting from CD-ROM (or any other device unsupported by the BIOS) behind the boot loader to the boot floppy (ie. boot session of the CD). As on-disk structure, we use standard gzipped TAR files that contain all the needed files.
The boot loader will start the kernel from the TAR file, and the running kernel will then detect the CD-ROM and try booting from there - at least that’s the theory. Right now, we have the TAR file system working in the userland boot loader test environment.
Getting Haiku to boot from CD to the usual Terminal window is my first assignment as an Haiku Inc. employee. If no unforeseen problems arise, I hope to get it done today or tomorrow.