## Re: [smartmontools-support] Disk Geometry - Slightly OT

 Re: [smartmontools-support] Disk Geometry - Slightly OT From: Franc Zabkar - 2009-11-19 03:55:47 ```Assuming there are 255 heads (aka tracks per cylinder) and 63 sectors/track, one can convert CHS geometries to LBA numbers as follows: LBA = (C x 255 x 63) + (H x 63) + (S - 1) Partition size (in sectors) = End LBA - Start LBA + 1 = (Ce - Cs) x 255 x 63 + (He - Hs) x 63 + (Se - Ss) + 1 where e/s are the end/start values of CHS. BTW, I notice that there appears to be a hidden area between partitions 1 and 2. It starts at 7/0/1 (LBA 112455) and ends at 7/2/59 (LBA 112639). Its size is 185 sectors. I wonder what Dell hides in there. I've only ever used the Windows version of dd, but I expect you could extract the hidden area as follows: dd if=ddrescue.bin of=hidden.bin bs=512 count=185 skip=112455 -Franc Al Grant wrote: >The following is taken from testdisk on a ddrescue.bin file and shows the >partition structure. > >Current partition structure: > Partition Start End Size in sectors > > 1 P FAT16 >32M 0 1 1 6 254 63 112392 >[DellUtility] > 2 P HPFS - NTFS 7 2 60 1312 109 13 20971520 >[RECOVERY] > 3 * HPFS - NTFS 1312 109 14 38913 37 36 604055552 >[Family] ```

 Re: [smartmontools-support] Disk Geometry - Slightly OT From: Franc Zabkar - 2009-11-19 03:55:47 ```Assuming there are 255 heads (aka tracks per cylinder) and 63 sectors/track, one can convert CHS geometries to LBA numbers as follows: LBA = (C x 255 x 63) + (H x 63) + (S - 1) Partition size (in sectors) = End LBA - Start LBA + 1 = (Ce - Cs) x 255 x 63 + (He - Hs) x 63 + (Se - Ss) + 1 where e/s are the end/start values of CHS. BTW, I notice that there appears to be a hidden area between partitions 1 and 2. It starts at 7/0/1 (LBA 112455) and ends at 7/2/59 (LBA 112639). Its size is 185 sectors. I wonder what Dell hides in there. I've only ever used the Windows version of dd, but I expect you could extract the hidden area as follows: dd if=ddrescue.bin of=hidden.bin bs=512 count=185 skip=112455 -Franc Al Grant wrote: >The following is taken from testdisk on a ddrescue.bin file and shows the >partition structure. > >Current partition structure: > Partition Start End Size in sectors > > 1 P FAT16 >32M 0 1 1 6 254 63 112392 >[DellUtility] > 2 P HPFS - NTFS 7 2 60 1312 109 13 20971520 >[RECOVERY] > 3 * HPFS - NTFS 1312 109 14 38913 37 36 604055552 >[Family] ```