Something that I was discussing with a couple of friends and we were unable to figure it out. In FreeBSD and OpenSolaris/Solaris when you partition a drive a partition is created that covers the whole disk:

```
da0s1c
c0d0s2

```

For example, the output of my main hard drive in my OpenSolaris server:

```
xistence@Keyhole.network.lan:/dev/rdsk# prtvtoc /dev/rdsk/c4d0s2
* /dev/rdsk/c4d0s2 partition map
*
* Dimensions:
*     512 bytes/sector
*      63 sectors/track
*     255 tracks/cylinder
*   16065 sectors/cylinder
*    7296 cylinders
*    7294 accessible cylinders
*
* Flags:
*   1: unmountable
*  10: read-only
*
* Unallocated space:
*       First     Sector    Last
*       Sector     Count    Sector 
*           0     16065     16064
*
*                          First     Sector    Last
* Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
       0      2    00      16065 117145980 117162044
       2      5    01          0 117178110 117178109
       8      1    01          0     16065     16064

```

What was the reasoning behind using partition 2? Why not partition 0? Where in the history of unix was this decided? What legacy feature did it serve at that point in time? With GPT partitioning that goes away entirely (from what I have found).

Just something interesting ...

Since [ParoX](https://serverfault.com/questions/5095/historical-question-why-does-slice-c-or-slice-2-cover-the-entire-disk/5133#5133) mentioned GPT style partitioning and how Solaris represents that in terms of vtoc layout, here is the output from one of my disks that is 1 TB and is in a ZFS array, and has automatically been set up with GPT:

```
xistence@Keyhole.network.lan:~# prtvtoc /dev/rdsk/c5d0
* /dev/rdsk/c5d0 partition map
*
* Dimensions:
*     512 bytes/sector
* 1953520128 sectors
* 1953520061 accessible sectors
*
* Flags:
*   1: unmountable
*  10: read-only
*
* Unallocated space:
*       First     Sector    Last
*       Sector     Count    Sector 
*          34       222       255
*
*                          First     Sector    Last
* Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
       0      4    00        256 1953503455 1953503710
       8     11    00  1953503711     16384 1953520094

```