This is part of output of
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x000140bd Device Boot Start End Blocks Id System /dev/sdb1 2048 167774207 83886080 7 HPFS/NTFS/exFAT /dev/sdb2 167774208 1740638207 786432000 7 HPFS/NTFS/exFAT /dev/sdb3 * 1740638208 1935673343 97517568 83 Linux /dev/sdb4 1935673344 1952448511 8387584 82 Linux swap / Solaris
But when I multiply 255*63*121601 i get 1953520065 sectors which is less than 1953525168 sectirs reported by fdisk. The difference is 5103 sectors.
I know that the number of heads, sectors/track and cylinders reported does'n probably refer to real hardware properties and that is was somehow calculated for backward compatibility. But I still wonder what did hapen with those 5103 sectors? Can I use them?
Later I wanna move filesystems, do some changes, change partition table and use combination of GPT and MBR. That is why I want to know everything about sectors on my disk. My changes will include backing up with dd utility before start and after completing changes. I want to back up GPT sectors. Even those ones which should reside in last 34 sectors of HDD. But now I wonder where last 34 sectors are. On the reported end or on the place I calculated?