After choosing "Guided - Use entire disk" during installation of Ubunsut Server 12.04 I find that the first partition starts on sector 34. Why that specific sector and not the first one?

(parted) print

Model: ATA WDC WD30EZRX-00M (scsi)

Disk /dev/sda: 5860533168s

Sector size (logical/physical): 512B/4096B

Partition Table: gpt



Number  Start    End          Size         File system  Name  Flags

 1      34s      390659s      390626s      fat32              boot

 2      390660s  890660s      500001s      ext2

 3      890661s  5860533118s  5859642458s



(parted)

In case you prefer bytes as the unit:

(parted) unit B

(parted) print

Model: ATA WDC WD30EZRX-00M (scsi)

Disk /dev/sda: 3000592982016B

Sector size (logical/physical): 512B/4096B

Partition Table: gpt



Number  Start       End             Size            File system  Name  Flags

 1      17408B      200017919B      200000512B      fat32              boot

 2      200017920B  456018431B      256000512B      ext2

 3      456018432B  3000592956927B  3000136938496B