[illumos-Discuss] multiboot-fu needed

[Andrew Gabriel]

Mike Riley wrote:
> On 09/15/10 07:53, Garrett D'Amore wrote:
>> If you plan ahead for this and use slices (which are kind of like
>> 'partitions in a partition') intelligently, you can have many different
>> installs of Solaris.  I think on x86 hardware up to 16 slices are
>> supported on a given partition.   (On SPARC its only 8.)
> 
> Correct about the slices.  An RFE I filed way back when proposed a way 
> to let SPARC also get 16 slices.  The only reason it still has 8 is for 
> backwards compatibility with SunOS.

The VToC format is quite different.
Sparc obviously has to maintain compatibility with OBP.
x86 uses the SVR4 VToC format which is why it gets 16 slices (and if you 
patched the FDISK partition type, its disks were just about 
interchangeable with other SVR4's unixes, back when there were some 
other SVR4's).

> The idea of the RFE was so that removable disks from an X86 system could 
> be read and written on a SPARC system for data interchange.

Well, ZFS on GPT/EFI has done that now (except for the boot disk).

> Unless format has been updated you can only view and set the slices past 
> 7 using prtvtoc/fmthard.

I also fell over live upgrade grub boot support breaks with slice 
numbers > 9 (i.e. more than a single digit).

> As you should be able to tell from my posts on this thread, I have been 
> inside this code for years, and have wanted to fix it forever...

I always wanted the *p0 device on sparc (whole disk, regardless of any 
slicing/partitioning). It was difficult to use disks on sparc which had 
some alien OS's partitioning scheme, but it works fine on x86, using the 
*p0 device and decoding the alien OS's partitioning in your own software.

-- 
Andrew