site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com Shantonu On Aug 1, 2006, at 10:11 AM, Howard Gayle wrote: On 10.4.7, diskutil (or Disk Utility) places an area of 262144 512-byte blocks after each GPT partition, except the last partition, which gets 262151 512-byte blocks. Here's an example of partitioning a 320 GB disk into 7 partitions: diskutil partitionDisk disk1 7 GPTFormat \ 'Journaled HFS+' s01b_root0 53.9G \ UFS s01b_utils0 43.2G \ 'Journaled HFS+' s01b_root1 53.9G \ UFS s01b_utils1 43.2G \ 'Journaled HFS+' s01b_root2 53.9G \ UFS s01b_utils2 43.2G \ 'Journaled HFS+' s01b_rest 1G Finished partitioning on disk disk1 /dev/disk1 #: type name size identifier 0: GUID_partition_scheme *298.1 GB disk1 1: EFI 200.0 MB disk1s1 2: Apple_HFS s01b_root0 53.8 GB disk1s2 3: Apple_UFS s01b_utils0 41.7 GB disk1s3 4: Apple_HFS s01b_root1 53.8 GB disk1s4 5: Apple_UFS s01b_utils1 41.7 GB disk1s5 6: Apple_HFS s01b_root2 53.8 GB disk1s6 7: Apple_UFS s01b_utils2 41.7 GB disk1s7 8: Apple_HFS s01b_rest 6.5 GB disk1s8 With an Apple partition map it looks like this: diskutil partitionDisk disk1 7 APMFormat \ 'Journaled HFS+' s01b_root0 53.9G \ UFS s01b_utils0 43.2G \ 'Journaled HFS+' s01b_root1 53.9G \ UFS s01b_utils1 43.2G \ 'Journaled HFS+' s01b_root2 53.9G \ UFS s01b_utils2 43.2G \ 'Journaled HFS+' s01b_rest 1G Finished partitioning on disk disk1 /dev/disk1 #: type name size identifier 0: Apple_partition_scheme *298.1 GB disk1 1: Apple_partition_map 31.5 KB disk1s1 2: Apple_HFS s01b_root0 53.8 GB disk1s3 3: Apple_Boot 8.5 MB disk1s4 4: Apple_UFS s01b_utils0 41.9 GB disk1s5 5: Apple_HFS s01b_root1 53.8 GB disk1s7 6: Apple_Boot 8.5 MB disk1s8 7: Apple_UFS s01b_utils1 41.9 GB disk1s9 8: Apple_HFS s01b_root2 53.8 GB disk1s11 9: Apple_Boot 8.5 MB disk1s12 10: Apple_UFS s01b_utils2 41.9 GB disk1s13 11: Apple_HFS s01b_rest 6.7 GB disk1s15 3:17 Device block size=512, Number of Blocks=625142448 (298.1G) This time, the 262144-block area comes before each partition, and the one at the end is the same size. I didn't notice anything in IOApplePartitionScheme or IOGUIDPartitionScheme that seemed to be looking for these areas. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... They're for future use by Apple, and are populated as needed for some boot methods, such as AppleRAID booting on PowerPC systems Now look what gpt(8) shows: sudo gpt -r -v show /dev/disk1 gpt show: /dev/disk1: mediasize=320072933376; sectorsize=512; blocks=625142448 start size index contents 0 1 PMBR 1 1 Pri GPT header 2 32 Pri GPT table 34 6 40 409600 1 GPT part - C12A7328-F81F-11D2- BA4B-00A0C93EC93B 409640 112774352 2 GPT part - 48465300-0000-11AA- AA11-00306543ECAC 113183992 262144 113446136 90334824 3 GPT part - 55465300-0000-11AA- AA11-00306543ECAC 203780960 262144 204043104 112774352 4 GPT part - 48465300-0000-11AA- AA11-00306543ECAC 316817456 262144 317079600 90334824 5 GPT part - 55465300-0000-11AA- AA11-00306543ECAC 407414424 262144 407676568 112774352 6 GPT part - 48465300-0000-11AA- AA11-00306543ECAC 520450920 262144 520713064 90334824 7 GPT part - 55465300-0000-11AA- AA11-00306543ECAC 611047888 262144 611310032 13570232 8 GPT part - 48465300-0000-11AA- AA11-00306543ECAC 624880264 262151 625142415 32 Sec GPT table 625142447 1 Sec GPT header sudo pdisk e /dev/rdisk1 p Partition map (with 512 byte blocks) on '/dev/rdisk1' #: type name length base ( size ) 1: Apple_partition_map Apple 63 @ 1 2: Apple_Free 262144 @ 64 (128.0M) 3: Apple_HFS Apple_HFS_Untitled_1 112774352 @ 262208 ( 53.8G) 4: Apple_Boot eXternal booter 17408 @ 113036560 ( 8.5M) 5: Apple_UFS Apple_UFS_Untitled_2 90579560 @ 113053968 ( 43.2G) 6: Apple_Free 262144 @ 203633528 (128.0M) 7: Apple_HFS Apple_HFS_Untitled_3 112774352 @ 203895672 ( 53.8G) 8: Apple_Boot eXternal booter 17408 @ 316670024 ( 8.5M) 9: Apple_UFS Apple_UFS_Untitled_4 90579560 @ 316687432 ( 43.2G) 10: Apple_Free 262144 @ 407266992 (128.0M) 11: Apple_HFS Apple_HFS_Untitled_5 112774352 @ 407529136 ( 53.8G) 12: Apple_Boot eXternal booter 17408 @ 520303488 ( 8.5M) 13: Apple_UFS Apple_UFS_Untitled_6 90579560 @ 520320896 ( 43.2G) 14: Apple_Free 262144 @ 610900456 (128.0M) 15: Apple_HFS Apple_HFS_Untitled_7 13979832 @ 611162600 ( 6.7G) 16: Apple_Free 16 @ 625142432 What are they for? _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/ssen% 40opendarwin.org This email sent to ssen@opendarwin.org This email sent to site_archiver@lists.apple.com