Hi,

>  Almost. mkisofs can assemble such a ISO image - you need to write
> some additional information within the first 16 tracks of the CD.

Hmm, what, apart from an eventual BSD disklabel would you want to write
into the first 16 sectors (assuming you meant sectors above) of the CD?

In ISO9660, these are free, and El Torito doesn't use them either (well,
actually you may use this space for El Torito information, as well as you
may use it for e.g. Rock Ridge information, but both can be anywhere on disk).

> Also, El Torito does not support "large" chunks of FFS, only floppy-sized 
> images and (cannot look it up right now) small sized disk partitions. The 
> disk partitions need to be available as a file during the image construction 
> state (use 'dd' to do so). 

Actually, El Torito allows different ways for booting.

One way is to include a floppy image on the disk and point an El Torito
record to it.  The BIOS recognizes this and sets things up so that it
looks to the machine as though drive A: now contains exactly this disk
image (yes, there is support for 1.2M, 1.44M and 2.88M disk images).
Your real A: drive becomes B: and your real B: drive is lost.

You can also have a hard disk image of an LBA addressable disk on it.
This will become your C: drive (BIOS drive number 80), and all other
drives will accordingly be incremented, i.e. C: becomes D: etc.

And you can simply boot a memory image from the CDROM into memory and
just run that.

Clearly, at least the second option above will allow for large chunks of
FFS.  And you could also use the third option and boot a NetBSD kernel
with a CD driver and access the disk from there.  Note that this latter
would require some modifications, as the CDROM sector size is 2k and
we currently only support FFS on devices with 512 bytes sectors.

Of course, mkisofs doesn't support these latter options (or so I
understand).

Also note that I have to admit that I too only used the first option
myself to make bootable CDs.

Ciao,
Wolfgang
-- 
ws@TooLs.DE     (Wolfgang Solfrank, TooLs GmbH) 	+49-228-985800