On 10/12/05, Dennis Clarke <blastwave at gmail.com> wrote:
> ALL :
>
>   RE: 
> http://svn.genunix.org/repos/opensolaris/trunk/usr/src/cmd/fmthard/fmthard.c
>   and 
> http://svn.genunix.org/repos/polaris/trunk/usr/src/uts/common/sys/dklabel.h
>
>   For a long long time now I have been using 16 slices on the x86
> edition of Solaris. [1]

The number of partitions to support is an implementation choice:
http://svn.genunix.org/repos/polaris/trunk/usr/src/uts/common/sys/isa_defs.h
Look for _SUNOS_VTOC_8 or _SUNOS_VTOC_16.

I put there _SUNOS_VTOC_8 for PPC port since I think that both are quite
bad nowadays and we should go with EFI (aka GPT) label anyway. There
are plans to make EFI labeled disks bootable and I hoped to just stick to
it when it'll be available. EFI label should give you unlimited (in theory)
number of partitions, if I understood it correctly. Current Solaris
implementations
may limit it however.

BTW, lack of certainty on that subject is another reason to postpone the
PPC disk support meanwhile.

Regards,
      Cyril


>
>   This has worked fine and is quite stable and is based on the
> implemetation from the AT&T SVR4 spec it seems.  Within the Sparc
> world we have always been limited to 8 slices with the backup slice
> being an overlap of the whole disk by convention.  This seems to date
> way back to the SunOS days and BSD world.  J?rg will probably be able
> to provide illumination on that perhaps.
>
>   At this stage I am looking at the boot issues for the PowerPC port
> and also spending time looking at the process of getting the kernel
> booted up and the VTOC certainly comes into play here.  My hope is to
> implement the 16 slice (  _SUNOS_VTOC_16 ? ) approach to the logical
> partitions.  Are there any obvious pitfalls in this approach or am I
> labouring under a misconception about the implementation ?
>
> Dennis Clarke
>
> [1] this machine is running here with Solaris 2.5.1 for x86
> # uname -a
> SunOS tunafish 5.5.1 Generic_103641-42 i86pc i386 i86pc
> # prtvtoc /dev/rdsk/c0t2d0s0
> * /dev/rdsk/c0t2d0s0 partition map
> *
> * Dimensions:
> *     512 bytes/sector
> *     106 sectors/track
> *      10 tracks/cylinder
> *    1060 sectors/cylinder
> *    3954 cylinders
> *    3952 accessible cylinders
> *
> * Flags:
> *   1: unmountable
> *  10: read-only
> *
> *                          First     Sector    Last
> * Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
>        0      2    00       3180    197160    200339
>        1      7    00     200340    435660    635999
>        2      5    01          0   4189120   4189119
>        3      0    00     636000    524700   1160699
>        4      0    00    1160700     33920   1194619
>        5      0    00    1194620    410220   1604839
>        6      4    00    1604840    449440   2054279
>        7      0    00    2054280   1049400   3103679
>        8      1    01          0      1060      1059
>        9      9    00       1060      2120      3179
>        a      3    00    3103680    855420   3959099
>        f      0    00    3959100    230020   4189119   /usr/local
>
> This machine has a external HP C3010 2GB disk attached .. still
> spinning.  Who knows how old.
>
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