cd boot

BFS incompatibilities

Blog post by axeld on Mon, 2005-10-17 14:05
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First of all, I successfully booted Haiku from CD-ROM from several machines today. It took a bit longer than I thought, as no emulator that I have access to seems to support multi-session CDs, and not every BIOS I have works by the book. The boot device selection is still very simplistic, so it might not end up booting completely from CD if you just inserted it, and didn't choose "Boot from CD-ROM" in the boot loader - but you'll have to bear with that currently. I'll probably fix that tomorrow.
Anyway, you could build you own bootable CD image with the "makehaikufloppy" script that's now in our top-level directory (it's still rough, and you have to build the whole system manually or via "makehdimage" before). You just need "mkisofs" and use the resulting image in this way:

CD boot update

Blog post by axeld on Fri, 2005-10-14 15:10

Everything is in place now, and the boot loader is even passing all information to the kernel to be able to boot from a CD. It's not yet working though, as the VFS is only evaluating the partition offset of the boot volume, and nothing more.

It's probably only a tiny bit left, so I try to finish it tomorrow - in my spare time, as I usually don't work during the weekend :-)

We have also agreed on not making demo CDs (images only, of course) available before the whole system runs a bit more stable. Compared to a hard disk image, a CD image is likely to be tested by a lot more people - and therefore, the first impression should not be too bad.

CD boot

Blog post by axeld on Thu, 2005-10-13 10:53

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.

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