gpt and MS Windows


(A) Different Windows see a gpt disk differently.

32-bit Windows cannot see gpt disk interior. This is how a gpt disk showing up in Xp's disk management

[img]http://groups.google.com/group/hkexf...0one.gif?hl=en[/img]

It clear show the 2TB gpt as one partition. The other 1.5TB disk has a normal Msdos partition table.

The 64-bit Windows systems are a bit cleverer and a 64-bit Win7 sees the maximum 128 internal partitions as shown below.

[img]http://groups.google.com/group/hkexf...disk.PNG?hl=en[/img]

It is interesting to see the 64-bit sees the gpt disk as its own and attempts to mount all the partitions by assigning a letter to each until the drive letter runs out at z:. Then it stops.

This is a very unusual behaviour because a standard MS Windows does not mount a partition, gives it a drive letter if the filing system is not recognised. Yet it goes all its way to do it for the gpt disk.

I have also long been puzzled by MS Windows calling every partition it doesn't recognised or with a vaild filing system as a "primary" partition.

(B) gpt is a no go area for MS boot loaders

MS boot loaders from Dos, Win2k, Xp, Vista and Win7 all work on the principle that any one of the 4 primary partitions with the booting flag set "on" shall be booted. There is no distinction between primary and logical partition in a gpt disk and there can be potentially 128 partitions in each. Thus the MS boot loaders break down completly with a gpt disk. No wonder none of the 32 bit MS Windows can boot from a gpt disk.

The 64-bit MS Windows can boot from a gpt disk only if the motherboard is equipped with the efi hardware which provides its own boot loader. This will be very hard to catch on. In the mean time many MS Windows systems are reaching the end of the road with a hard disk limited at 2TB. May be the 4k physical block addressing will buy them some extra time.

The superiority of the Linux boot loaders is evident when comparing with the MS systems.

It comes no surprise that I found Lilo and Grub can work normally with a gpt disk.

Linux kernel is a lot saner when coming to partitions. Unless one specifies them in /etc/fstab none of the partitions will be mounted. If a user wants he/she can always mounts a partition manually or automatically with fstab.

A MS Windows system tends to be obssessed with other systems using their resources so on every boot-up it will go through every partition in each hard disk. This takes a long time and doing the disk no good at all.