Gerd Hoffmann wrote:
On 09/08/09 15:47, Jan Kiszka wrote:
Before setting this definitely useful feature in stone, I have two questions though:
- -drive ...,boot=on is logically in conflict with -boot. Yes, -boot for x86 currently cannot differentiate between multiple disks, only between boot media types. Still, this two-stage configuration is rather unintuitive and looks like a patchwork. Given that we have full control over all components, is it really the preferred approach? I already thought about, e.g., -boot c2 to select the second disk. Not that nice, but I would rather vote for a consistent configuration than a scattered one.
Disk numbers are bad. Define "second hard disk". Especially for a system with different kinds of disks (say one scsi and one virtio).
One could use the specification order, but I agree it's not very handy.
Drives have names though which can be used to reference the disks, so we could use that instead. -boot cmd line syntax becomes a bit tricky then though, we somehow have to figure whenever the user gave us names or old-style letters. Something like this ...
-drive if=virtio,id=sys,file=/path/to/disk.img -cdrom /path/to/install.iso -boot order=[sys],once=d,menu=off
Yes, this looks powerful and clean. One could even still define probe orders like "-boot order=[sys][backup]d".
... might work out nicely. I suspect the libvirt folks will hate us for that though.
Does anyone from libvirt want to comment on this?
- This is just an implementation detail: Do we really need to implement booting from virtio and scsi via an extension rom? Isn't it possible to merge the corresponding support into the main bios?
Well. There are quite a few. bochs pcbios, seabios, coreboot ...
Ok, but that's only an argument to have extboot as a workaround for bioses not yet supporting scsi and virtio natively, isn't it? I'm thinking long-term here, not arguing against a extboot-based short-term solution. Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux