[vbox-dev] New OS bring up with Vbox ?

[Klaus Espenlaub]

phi gcc wrote:
> Hi Mark,
> 
> 
>> See the user manual for details on the VBoxManage convertfromraw command.
>> It turns a raw disk image into a VDI (or other).
>>
> 
> Thanx, I spoted it in the mean time :) so i will use this along with
> other command as given by Huihong to handcraft the initial guest state
> for infent OS that don't have a boot  loader yet.

Another approach would be to replace the BIOS with your OS... only 
possible if you don't need the BIOS of course. VirtualBox supports 
specifying a custom "ROM image", but this is a really special way and 
you'd be completely on your own, starting in real mode at address f000:fff0.

If that's not an option (lots of work to e.g. set up the hardware etc 
etc) and you don't want to spend much time on your own boot loader, have 
a look at the off-the-shelf ones. A very flexible one is grub - it 
supports many boot variants (disk, net, ...) and supports loading both a 
kernel and modules in a microkernel style OS. The multiboot spec is 
quite straightforward (essentially a kernel in ELF format which contains 
some descriptor data structure). Etherboot/gPXE is also an option, and 
implements multiboot as well.

Back in my own kernel hacking days I used Etherboot (on an ISO image for 
maximum flexibility), as it turned out that network booting gave the by 
far best turnaround time. Today with the far more flexible gPXE you 
could even boot off an HTTP server...

The linux world has lots more bootloaders which could be relatively 
easily adapted - lilo, the syslinux family of loaders and many more. 
Reinventing the wheel is neither attractive nor necessary in this area I 
think.

Klaus

> Cheers
> Phi