GUID Partitioning Annoyance!

[donkey]

Hi there,

 

I have been using MBR and with that microsoft makes a system partition which can be converted in to a regular partition. BUT, on GUID partition, created with Snow or Leopard, I get junk partition for each partition that I choose to make so it is like this:

 

efi partition

partition 1

efi partition 2

partition 2

efi partition 3

partition 3

 

so 6! partitions in total... what am i doing wrong??

 

Thank you!!!

[srs5694]

Apple recommends, in Technical Note TN2166, that 128MB of free space be created after most partitions. The intent is that this space can be used by future disk partitioning tools to help implement features like filesystem resizing. My guess is that you're either seeing that free space as extra partitions for some reason (a bug in whatever you're using to view the partitions, perhaps) or there's a bug in Disk Utility (or whatever tool you used) that's creating EFI System partitions rather than empty space between partitions.

 

You might want to try using another tool to view your partition table to determine what's there. Also, try "ls /dev/disk0*" (or change "0" to another disk number) to see how the OS itself is viewing the partition table. For instance, if you get /dev/disk0s1 through /dev/disk0s6 in your example above, with no missing numbers, then the OS is really seeing six partitions; however, if you see /dev/disk0s1 through /dev/disk0s4, or if there are gaps in the number sequence, then the OS is seeing unallocated gaps, not "junk" EFI System partitions.

 

If this really bothers you or if you've really got "junk" EFI System partitions, you could delete them with another tool, or use another tool to create your partitions in the first place. GNU Parted should let you do this; however, it can be a bit flaky, and it'll erase your primary boot loader if you're using a BIOS-based system. My own GPT fdisk is another option. It provides a look at the disk that's closer to the way GPT is actually structured, but it's a text-mode tool that might be intimidating if you're not used to such things.

[donkey]

Apple recommends, in Technical Note TN2166, that 128MB of free space be created after most partitions. The intent is that this space can be used by future disk partitioning tools to help implement features like filesystem resizing. My guess is that you're either seeing that free space as extra partitions for some reason (a bug in whatever you're using to view the partitions, perhaps) or there's a bug in Disk Utility (or whatever tool you used) that's creating EFI System partitions rather than empty space between partitions.

 

You might want to try using another tool to view your partition table to determine what's there. Also, try "ls /dev/disk0*" (or change "0" to another disk number) to see how the OS itself is viewing the partition table. For instance, if you get /dev/disk0s1 through /dev/disk0s6 in your example above, with no missing numbers, then the OS is really seeing six partitions; however, if you see /dev/disk0s1 through /dev/disk0s4, or if there are gaps in the number sequence, then the OS is seeing unallocated gaps, not "junk" EFI System partitions.

 

If this really bothers you or if you've really got "junk" EFI System partitions, you could delete them with another tool, or use another tool to create your partitions in the first place. GNU Parted should let you do this; however, it can be a bit flaky, and it'll erase your primary boot loader if you're using a BIOS-based system. My own GPT fdisk is another option. It provides a look at the disk that's closer to the way GPT is actually structured, but it's a text-mode tool that might be intimidating if you're not used to such things.

 

Thank you for the Rod! The thing is that under OS X, the partitions do not show up... they only show up during the install process of windows vista/7, the part where you choose where windows should be installed.

 

Thanks again!

[srs5694]

A lot of partitioning tools don't really accurately represent what's on the disk; they fudge things in one way or another, usually in an effort to make the utility more user-friendly. This is definitely true of Disk Utility, it's true of GNU Parted and its brethren (in a different way), and it may be true of the tools that Windows uses during installation (I can't speak to that one directly). If you want to know what partitions are really on the disk, you need to use a low-level utility. My own GPT fdisk will do this for GPT volumes, which you seem to be using. I believe the standard text-mode diskutil program that comes with OS X will show you what's really there, too, but I can't guarantee that for all cases.