:: VTOC (Volume Table of Contents)
VTOC has the information of disk's controller, geometry and slices(partitions).
The first sector of disk has VTOC.

:: format
Format command loads VTOC on memory, so you can modify it.
By modifying VTOC you can create or remove partitions.
You have to excute 'label' after you finish modifying VTOC,
so the new VTOC can be saved and effective.

:: Backing up VTOC
1. On the format command, excute 'save' to back up VTOC.
The back up file is /etc/format.dat(recommanded path).
To restore VTOC, excute 'select'.
2. Use 'prtvtoc' command for direct VTOC backup.
(ex : #prtvtoc /dev/rdisk/c#t#d# > /vtoc/c#t#d#)
You can use 'fmthard' for VTOC backup.