For PPC start the pfdisk program with the appropriate harddisk option. The pdisk syntax is a little bit different than fdisk syntax, if you are familiar with fdisk.
To create a linux capable partition using the available free space, type c followed by the partition designation of the free space pX, the size in MB of the desired partition <size>M and the name of the partition <name>. The example below creates a 1.8 GB partition name root starting at the beginning of the free space designated as partition 6: c p6 1800M root