UEFI GTP fdisk is a disk partitionning tool running under UEFI/BIOS
UEFI GPT fdisk is a port to UEFI of the famous GPT fdisk partitioning tool, see http://sourceforge.net/projects/gptfdisk/ . Now since this program runs directly under UEFI shell you don't need to *boot* the system to convert/edit partition tables.
This simplest form of this project is the make a file in the file system appear as a disk. This kernel driver allows the user programs to create, delete and service SCSI low level HBA (LLD). The user program can create, register and service SCSI HBA.