Thread: Installation uses fdisk or gdisk depending on hardware?

hello again,

noticed strange.
have installed 10.04 64bit on 2 machines have different hardware.
after installation (that went way), needed add extra
partitions on both machines. use fdisk this, , on 1 machine went ok. on second machine, however, after starting fdisk, got warning message guid partition table found on disk, , fdisk not compatible.
leads me believe during installation on first machine fdisk used partition harddisk, , on second machine gdisk or gparted used.

normal ?
there way @ installation time force use of fdisk ?

hope knows answer this.

thanks,
hans

the ubuntu installer uses neither fdisk nor gdisk; uses partitioning tool based on libparted, core of gnu parted, gparted, palimpsest disk utility, , other tools. can use fdisk manipulate master boot record (mbr) partitions , few other obscure partition types; gdisk manipulate guid partition table (gpt) partitions , translate between gpt , mbr; , libparted handle (but not translate between) various partition table types, including both mbr , gpt.

don't know exact rules ubuntu installer uses decide partition table type use, believe following true:

• if disk has existing partition table, installer uses rather creating new one; creates new table if disk has none, or possibly if tell wipe disk clean (i've not checked last detail).
• if computer uses (u)efi firmware, installer uses gpt when creates new partition table.
• if disk on size (something between 1tb , 2tb), installer uses gpt when creates new partition table.
• if disk under size and computer uses bios firmware, installer uses mbr when creates new partition table.

thus, suspicion gpt-using computer had disk gpt partitions, had disk on 1tb in size, or based on uefi. depending on of case, , perhaps more precise details, might or might not want override decision use gpt. instance, mbr inadequate disks of on 2 tib, if you've got 3 tb disk or raid array of on 2 tib, pretty have use gpt use whole disk. (there risky ways use mbr disks of 4 tib, recommend against use.)

on sub-2tib disks, gpt has advantages on mbr, such no distinction between primary, extended, , logical partitions; backup of partition data on disk; crcs of partition data can spot errors; labels partitions; , no more use of chs addressing (except in protective mbr). thus, linux-only installation, imho gpt superior partitioning system mbr. biggest advantage of mbr in compatibility wide variety of oses. windows, in particular, can boot gpt disks on uefi-based computers, mbr better choice on dual-boot bios-based computer. (on uefi, though, windows equally wed gpt.)

if want use mbr rather gpt, can setting disk in mbr before installing ubuntu. might not need create partitions, set basic mbr structures. if disk has gpt data, though, you've got utility understands gpt @ least enough wipe old gpt data. if don't that, libparted-based tools confused , tend report disk unused, or use old gpt data rather new mbr data.

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